DIPTERA. — LEPTIDE. 551 
transformation of Thereva nobilitata (Syst. Beschr. vol. ii. p. 117.), 
the larva of which he found in rotten wood. L’Admiral has also 
figured the larva, pupa, and imago of an insect which appears to me 
to be a large species of Thereva. (Naauw. Waarn. tab. 19.) 

The Leprrip# (Leptides Zaér., Rhagionides Laér. olim) (jig. 130.1. 
Leptis scolopacea) are distinguished from the Therevide, to which they 
Fig. 130 

are very nearly allied, by having the palpi large, externa , filiform or 
conical; the proboscis large, fleshy, and terminated by two elongated 
labial lobes (fig. 130. 2. mouth of Leptis); the antenne are inserted 
near the base of the head, with the third joint either short and rounded 
or kidney-shaped, and terminated by a long seta (fig. 130. 3. antenna 
of Leptis); the tarsi are terminated by three pulvilli; the wings are 
divaricate, and exhibit several perfect cells; the external nerve is 
furcate ; the middle and posterior tibiae have two apical spurs. 
The species are of a moderate size, and generally varied in their 
colours, their wings being occasionally spotted. The species of the 
typical genus frequent the trunks of trees, especially preferring the 
sides exposed to the sun. On alighting, their first movement is to 
place themselves in a position with the head downwards. Other species 
frequent low plants, grass, &c. 
De Geer has observed that the females deposit their eggs either in 
the earth or in vegetable mould. The larve ( fig. 130. 4.) are elon- 
gate, apod, subcylindrical grubs, with the posterior segments gradually 
widening, and terminated behind in two points, heneath which is an 
oblique truncation with two spiracles (jig. 130. 5.); the head is 
small, scaly, and bears a pair of antenne in the typical genus (Bouché, 
NN 4& 
