402 



acle, spiracular openings irregular; a group of 3-4 hairs on a slight 

 elevation below each spiracle. 



Pupa (PI. LVII, Fig. 5).— Length, 6-8 mm. Yellowish testa- 

 ceous, the armature brown. 



Head without prominent thorns, the bases of antennae produced 

 in the form of carinate ridges; proboscis thick, elongated. Thoracic 

 respiratory organs in the form of short stalks; surface hairs as in 

 figure. Abdominal spiracles elevated ; armature as in figure, the 

 bristles rather slender. 



The foregoing descriptions were made from material obtained by 

 me at White Heath, 111., April 2, 1916, from a much-decayed tree- 

 stump. I reared a number of specimens of both sexes under labora- 

 tory conditions, the specimens emerging from ten days to three weeks 

 from date of collection of the larvae, the average duration of the 

 pupal stage being 8 days. No parasites were obtained. 



No imagines of this species were obtained by collecting in the 

 locality where the larvae were taken, and the species is unrepresented 

 in our Laboratory collection except by the reared examples. 



Originally described from Maryland and Massachusetts, the spe- 

 cies has not, so far as I know, been subsequentlv recorded. 



Drapetis Meigen 



I have seen the larval and pupal exuvia of but one species of this 

 genus, and these are not in very good condition. This species, nigra 

 Meigen, is slightly less than 1.5 mm. in length, and as the exuvia 

 were dried out when I found them the details are not as clear as they 

 would be in fresh material. The drawings, however, give a good idea 

 of the general appearance of the parts available for study. 



HABITS OF LARVAE 



The larvae occur under bark and in decaying wood. Their very 

 small size makes their detection difficult. They spin a remarkably 

 tough cocoon, in which they pupate. The cocoon is densely coated 

 with minute particles of the wood in which the larvae live. 



HABITS OF IMAGINES 



The imagines are very common on tree-trunks and fences, run- 

 ning with great rapidity, and are predaceous upon small insects. They 

 resemble the dolichopodid genus Medeterus in both larval and adult 

 habits. 



