Taken from:
R. M. Bohart and L. S. Kimsey. 1982. A Synopsis of the Chrysididae in America North of Mexico.
Hedychrum cupricolle Cresson
Hedychrum cupricolle Cresson 1865:305. Lectotype female, Colorado (ANSP).
Discussion: This is the most colorful species of Hedychrum in the Western Hemisphere. Its color ranges from bright green to greenish gold to copper on the thoracic dorsum. The rest of the body is green to blue to blue violet. The contrasting color of the propodeum and the thoracic dorsum is a conspicuous and definitive character. It closest affinities are with nigropilosum by the green sterna, black hair and V-shaped depression at the dorsal end of the scapal basin. H. nigropilosum may have the V-shaped depression at the dorsal end of the scapal basin obscured by a large pit in the middle of the depression. H. cupricolle differs by the black hair being short, less than 1.5 MOD long (compared to nigropilosum with hair 1.0 MOD or greater). It is also a little larger than nigropilosum (9-11 mm long versus 5-9 mm). They are sympatric only in Utah.
Material examined: 36 males and 28 females.
Distribution: Utah and Wyoming to Illinois and Michigan. Specimens were collected from July to September.
Hedychrum Latreille
Larry D. French
Hedychrum Latreille 1802:317. Generotype Chrysis lucidula Fabricius 1775 (Sphex nobilis Scopoli 1763), original designation.
Diagnosis: Tarsal claw with a single subsidiary tooth, appearing bifid (fig. 134), hindtibia (in some species also midtibia) with a pit or depression on posterior surface towards apex, medial vein weakly curved (fig. 135), frons along inner eye margins and scutellum with rather even and close punctation, scapal basin with strong transverse ridging, RS stub extending apicad at least as far as stigma, median cell of forewing setose, female sternum Ill with a subbasal sulcus extending from lateral margin at least halfway to midline (fig. 150) and with an apicomedial tooth (in all New World species) (fig. 150).
Discussion: Hedychrum of North America as treated here contains nine species. Most are rather common, medium sized greenish to bluish wasps found in mountain areas associated with sandy soils. A total of 3, 550 specimens were examined for this study.
Members of this genus are known to be nest parasites of sphecid wasps of the tribe Cercerini that provision their nests with adult curcullonids. However, little has been published on the biology of Hedychrum beyond a few records of association with the hosts.
The most recent synoptic works on Hedychrum were by Aaron (1885) and Norton (1879), both of whom were hindered by having too few specimens and an unclear concept of the genus. Therefore, they had problems with the distinction between Hedychrum and other closely related genera.
It is now clear that the hindtibial pit, bifid tarsal claws and sub- basal sulcus of sternum III make Hedychrum easy to distinguish. One closely related genus that might pose a problem in identification is the recently described Hedychreides Bohart from western North America. This wasp has bifid tarsal claws but it lacks the well-defined hindtibial pit and transverse ridging in the scapal basin.
Sex determination in most elampine genera is a difficult task at best. Hedychrum is an exception to this rule with three useful characters for sexing individuals. Females have an apicomedial tooth and a subbasal sulcus on sternum UI (fig. 150), whereas males have none (fig. 151). Also, the anterior face of the hindfemur in females is smooth and shiny green, whereas in males it is reticulate and dull brown.
Male genitalia in most chrysidids are useful for species distinction. However, in Hedychrum their value appears to be limited. In a few species there are slight differences in the shape of the distal end of the paramere and in one species (spiloventer) the cuspis is club shaped.
Key to Hedychrum
1. S-II-III extensively green to blue
2
S-II-III brown, except S-II or III may have a small spot of green to blue medially
4
2. Thoracic dorsum green to gold, contrasting with blue to blue green of propodeum, body length 9-11 mm
cupricolle Cresson
Body uniformly green to blue, less than 9 mm long
..3
3. Hindtibial hair and T-III apical hair black mostly 1.5 MOD long, T-I smooth subbasally fig. 158), female S-III apical tooth not bibbed (fig. 150)
..nigropilosum Mocsary
Hindtibial hair white to light brown, T-III apical hair white to black, both T-III
apical hair and hindtibial hair mostly 1 MOD long, T-I basally with three or more longitudinal carinae (fig. 159), female S-III apical tooth bibbed (fig. 149)
parvum Aaron
4. Body hair black, sterna brown, body blue to bluish purple, male pedicel brown
.wiltii Cresson
Body hair white to light brown, never black; sterna brown or sometimes with a medial green spot; body green to greenish blue; male pedicel green to blue
5
5. Forefemur with distinct subbasal angle (fig. 136), hindtibial pit almost reaching base
of tibia (fig. 142)
boharti French
Forefemur rounded subbasally (fig. 137), hindtibial pit restricted to apical fourth
of tibia (fig. 140)
..6
6. Hindtibial pit very small (fig. 141), abdomen with brown to violet spot dorsomedially
.punctum French
Hindtibial pit not reduced (fig. 140), abdomen uniformly green to blue
.7
7. Tergum I with sublateral punctures contiguous, less than 0.25 PD apart (fig. 153), and more than four well developed carinae running from base halfway to summit (fig. 156)
.confusum Buysson
Tergum I with sublateral punctures not contiguous, more than 0.25 PD apart (figs. 154 and 155), and four or fewer carinae running from base halfway to summit (fig. 157)
.8
8. Body length 8-10 mm, sternum II brown, impunctate area laterad of lateral ocellus greater than 1.0 LOD across (fig. 146), head in dorsal aspect 2.5 times as wide as long (fig. 146)
violaceum Brulle
Body length 4-5 mm, sternum II with green spot medially, impunctate area laterad of lateral ocellus less than 1.0 LOD across (fig. 147), head in dorsal aspect twice as wide as long (fig. 147)
.spilovener French
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