386 



Body cylindrical, the segments well defined, but little longer than 

 broad, and without well-developed locomotor elevations; apical seg- 

 ment much longer than the one bearing the spiracles, slightly but dis- 

 tinctly carinated on its upper posterior margin and with the normal 

 8 long hairs — 4 on dorsum and 4 on venter. 



The foregoing details were obtained from specimens I obtained 

 at White Heath, 111., in April, 1916, some of which produced imagines 

 in May. The larvae occurred in a much-decayed tree-stump in a wood 

 along the Sangamon River. In the same stump occurred many larvae 

 of Rhaniphouiyia diuiidiata Loew, and also various coleopterous 

 larvae, the latter including Elateridae, Tenebrionidae, Cerambycidae, 

 and a few others that are usually found in rotten wood. 



The pupa I described in the paper mentioned just after the fami- 

 ly key. 



Asii^us sERicEus Say 



Asilus sericeus Say, Jour. Acad. Nat. Sei. Phila., Vol. 3, 1823, p. 48. 



Asilus hcrminius Walker, List of Ins. Brit. Mus., Dipt., Vol. 2, p. 410. (1849) 



Puha. — Length, 20 mm. Brownish testaceous, head and thorax 

 very distinctly shining, abdomen less so, armature and spiracles deep 

 brown. 



Upper pair of cephalic processes stout, acutely pointed, apical half 

 of dorsal surface smooth, basal half longitudinally, coarsely striate, 

 bases irregularly rugose ; viewed from above, processes slightly 

 divergent apically, the distance between them at apices about equal to 

 length of either thorn; lateral cephaHc process as in Figure 2, Plate 

 LV, the projection on under surface of base of lower thorn rather 

 large; lateral pieces of mouth-parts not carinate at apices, the upper, 

 central portion with a distinct protuberance. Thoracic spiracle very 

 much elevated, apex compressed, the whole presenting the appearance 

 of a short compressed tube; the pair of thorns at base of middle leg 

 contiguous basally, anterior one very much smaller than posterior, the 

 latter as large as lower thorn of lateral cephalic process (Fig. 3) ; 

 protuberance above wing-base with a small chitinized process on lower 

 portion of posterior margin ; wing with very faint indications of dis- 

 cal protuberance ; apices of wings extending to apices of fore tarsi. 

 Abdominal spiracles similar in form to those of thorax but smaller; 

 first dorsal segment with 12 stout, upwardly directed thorns the apices 

 of which are slightly turned backward ; segments 2-7' each with 6 

 long, stout, acutely pointed thorns, and between the pairs on second 

 segment are cither i or 2 shorter stout thorns which are not less than 

 half as long as the large thorns, the la.tter becoming progressively 



