EXPERIMENT STATION BULLETINS. 285 



ocelli are prominent and intense black. The 



antenna? are black with fifteen joints. The first 



two are rounded, the remaining ones elongated. 



The palpi are whitish yellow. The entire thorax isj 



shining black. The wings are transparent and 



iridescent. The venures and stigma are dusky. 



The front legs are yellow, the middle ones yellow or 



dusky, the posterior ones usually dusky. All the 



legs have a yellowish tinge and may vary between 



yellow and dusky. The first joint or petiole of the 



abdomen is yellow, the remaining segments black or Flgl 8— Male - 



dusky. Underneath the thorax is black, the abdomen yellowish, becoming 



dusky or black toward the tip. The length is one sixteenth of an inch. 



Described from several specimens. 



PAKASITES ON HETROCAMPA SUBALBICANS. 



The common linden caterpillar, Heterocampa subalbicans, Grote, was 

 exceptionally common in central Michigan in 1890. This gray moth, 

 variously marked with black and white, lays her eggs on basswood and 

 elm. The larvae, which are often very common in autumn, are wondrously 

 beautiful and varied. The combination of delicate green and brilliant red 

 is exquisite. 



During the past autumn, we found about the larva? on the leaves, sym- 

 metrically arranged, often in a circle ; groups of pupa? of some parasite. 

 These pupa? were remarkable for their abundance, their style of arrange- 

 ment, and for a mass of fecal matter adjacent to each one. Thus they 

 formed curious objects, and though so minute, attracted the attention o£ 

 several of my students. 



From these pupa?, which in some cases we derived from the larva?, we 

 reared two very interesting chalcid parasites, a few black ones, of the genus 

 Cratotechus, which I think were probably the real parasites of the cater- 

 pillar, and many more beautiful, shining metallic green of the genus 

 Derostenus. In several cases we reared only species of these latter, though 

 in many cases we got both species and both sexes from the same group of 

 pupa?. 



THE BEAUTIFUL DEROSTENUS. 



The nine-jointed antenna?, four-jointed tarsi, broken sub-marginal vein, 

 narrow costal cellure, short post-marginal and stigmal veins, single spur to 

 the posterior tibia?, two bristles to the sub-marginal vein, small metapleura r 

 and double bristles on the mesoscutellum, determine the sub- family Ente- 

 donina?, as given by Howard in his synopsis (Entomologica Americana 

 Vol.1, p. 198). 



The funicle of the male antenna? is not toothed, the mesoscutellum has 

 no median furrow, wings with no appearance of cells, even from the arrange- 

 ment of hairs; post marginal vein unbroken, abdomen short, and antenna? 

 nine-jointed; thus we know that this resplendent Chalcid belongs to the 

 genus Derostenus (see Howard's Synopsis Entomologica Americana 

 Vol. 2, p. 100). 



