336 

 Ndopachygaster MACUI.ICORNIS Hine 



Pachygaster macuUcornis Hine, Ohio Nat., Vol. 2, 1902, p. 228. 



Larva and Pupariifin. — Length, 3-4 mm. Pale testaceous, un- 

 marked. 



Head similar to that of BupacJiygastcr Jicnshawi in general ap- 

 pearance, the bristles noticeably shorter. Armature of body similar 

 in arrangement to that of JicnsJiazci but the bristles much shorter, 

 their relative lengths on penultimate and ultimate segments as in 

 Figure 6, Plate XLIX. 



The larvae of which the foregoing is a brief description, were ob- 

 tained under the bark of fallen elm-trees at White Heath, 111., in 

 March and April, 1916. I reared a large number of imagines from 

 the larvae, and have also many of the latter alive in the laboratory 

 now (January, 1917) which I took under similar conditions in the 

 forestry of the University of Illinois October 21 and 28, 19 16. The 

 larvae feed upon decaying matter under the slightly loosened bark, 

 but also, occasionally, on other dipterous larvae — as on those of 

 Lonchaca polita, which are found along with them. Lonchaca larvae 

 often eat other larvae and puparia — as do also those of Bnxesta, which 

 frequents the same habitat — in fact the dipterous larvae found under 

 bark under conditions suitable for Stratiomyiidae appear to be 

 almost without exception alternately predaceous or saprophagous. 

 They may be able to live entirely upon the sap and slightly decayed 

 vegetable matter under the bark but I suspect that the main food sup- 

 ply consists of excreta, exuvia, or the bodies of coleopterous larvae 

 that occur there. That they feed upon each other I have proven by 

 personal observation. 



EuPACHYGASTER Kertesz 



I obtained a single larva of this genus under the loose bark of an 

 apple-tree at Savoy, 111., May 4, 1916, from which I succeeded in 

 rearing a female imago. A comparison of the larva wdien found with 

 a figure of that of Bupachygaster tarsalis Zetterstedt convinced me 

 that I had one that was congeneric with that species, and as I had 

 provisionally placed but one North American species in that genus 

 I was particularly anxious to discover whether my diagnosis of the 

 imagines was correct. I was therefore much gratified to find that 

 the resultant imago agreed generically with the species I had placed 

 in this genus. 



I subsequently obtained many larvae of the genus at Urbana, most 

 of which are still alive (January 191 7). 



