Asilidae. 17 



of the front and hind tibiæ, less dense on tlie middle libiæ. The 

 tarsi have strong bristles, and are densely haired on the lower surface. 

 The claws are strong; there are two pulvilH and a somewhat claw- 

 shaped empodiuni. Wings somewhat long and broad, the subcostal 

 cell open, the cubital vein forked, between the discai cell and the 

 iipper branch of the postical vein a postical cross-vein; five posterior 

 cells, all open ; the anal cell narrowly open, or closed. Alula developed 

 but small. The alar squamula small, hairy at the margin especially 

 tow^ards the angulus. 



Of the developmental stages I have only examined the pupa; the 

 larva is described by Beling (Arch. f. Naturgesch. Jahrg. 48, 1882, 

 195 — 99). It is cylindrical, white, fmely striated longitudinally. The 

 head is retractile, with some long, stiff hairs. The front part of the 

 first thoracic segment densely beset with small tubercles. The apex of 

 the body more or less pointed. The second, third and fourth segments 

 each with two bristles, and some similar bristles on the last segment. 

 Prothorax and the penultimate (or the marked off front part of the last) 

 segment each with a pair of small spiracles. The pupa is yellowish 

 white; the antennal sheaths are in front of the head, directed to 

 each side across the eyes; they have a strong, downwards curved 

 spine at the base and are sharply compressed, on the lower side 

 forming three strong spines. About at the base of the wing-sheath 

 there is an obliquely placed small, sharply compressed tubercle. The 

 abdominal segments have each a transverse row of long, at the apex 

 recurved, brown spines alternating with small spines on the dorsal 

 side; the last segment has on the dorsal side two long spines, at the 

 apex a pair of spines curved slightly upwards and a pair of small 

 spines beneath these. On the ventral side each segment has a trans- 

 verse row of long, thin, white hairs, the rows going over the lateral 

 margins a little up on the dorsal side to the dorsal rows of spines. 

 There is a pair of prothoracic and seven pairs of abdominal spiracles, 

 all small. The sheaths of the legs reach to the hind margin of the 

 second abdominal segment. 



The larvæ live in humous earth in woods and thickets; they 

 hibernate and the transformation to pupa and escape of the imago 

 take place in the following spring and summer. 



The species of Dioctria are somewhat characteristic by their more 

 or less slender shape and the generally rather long and broad wings. 

 They occur in grass and herbage on fieids, meadows and fens and 

 both in and outside woods. The prey of this genus is generally 

 smaller insects, though the larger species as oelandica may also take 

 somewhat large prey ; I have taken D. rufipes with a Sphecodes as prey. 



Diptera Danica. II. 2 



