397 



with an oval body and long proboscis ; the wings have the 

 three basal cells much prolonged, with the anterior intercal- 

 ary vein present almost without exception, the posterior always 

 wanting. The third joint of the antennae is simple, and the 

 empodium quite rudimentary. They are exceedingly swift on 

 the wing and are found in sunny paths and glades early in the 

 spring and throughout the summer. They can only be cap- 

 tured when alighted on the ground. The eggs are laid in the 

 nests of bees, and the half cylindrical, long, fleshy, smooth, 

 unarmed larvae devour the bee larvae, while the pupa is spiny, 

 armed on the head with horny lamellae. In the genus Bomby- 

 lius the body is ovate, with long dense hairs and a small head. 

 The eyes of the male are grown together, and the legs are very 

 slender. A species is known in England to lay its eggs at the 

 opening of. the holes of Andrena, whose larvae and pupae are 

 devoured by the larvae of the fly. Systropus is very long and 

 slender, and wasp-like, as in Conops, with the proboscis equal-, 

 ling the thorax in length. The genus Anthrax is more flattened 

 and oblong in shape than Bombylius, with a short proboscis ; 

 the eyes are not connected in the males. The species are 

 gaily colored, the wings often partially black ; they fly in paths 

 in the hottest days of summer. The larvae are parasitic on 

 bees, and in their transformations closely resemble those of 

 Bombylius. Audouin has found Anthrax morio in the nest of 

 Anthophora, and Westwood has found the pupa-skin in the 

 nest of Megachile, while the larva has, in England, more re- 

 cently been found to be parasitic in the nests of certain An- 

 drenidae. We have received from Mr. J. Angus the larva and 

 pupa (Plate 4, figs. 6, 7) of Anthrax sinuosa Wiedemann, 

 which is parasitic in the nest of Xylocopa Virginica. 



SYRPHID^: Leach. These gaily colored flies, so useful to ag- 

 riculturists from their habit of feeding upon Plant-lice, closely 

 resemble the wasps in form and coloration, having hemis- 

 pherical heads, large broad eyes, and rather flattened bodies 

 ornamented with yellow bands and spots. The wings have the 

 three basal cells much prolonged, the third longitudinal vein 

 simple, a spurious longitudinal vein between the third and fourth 

 longitudinal veins ; while the fourth longitudinal vein is united 



