ATHERICERA ; SYRPIIID/E, OR WASP-FLIES. 201 



the preceding, upon the juices of flowers. In general the pro- 

 boscis is comparatively short ; but in a few instances, as in the 

 Nemestrina longirostris^ it is of extraordinary length (Fig. 321). 

 This section also contains several other families of less interest 

 and importance ; among them we may mention the ASILID^E, 

 which live by rapine, seizing Flies, Tipulae, Humble- Bees, and 

 even Wasps, and sucking their juices. 



731. Section IV. ATHERICERA. The Dipterous insects of 

 the fourth tribe are principally vegetable-feeders in their perfect 

 state, only a few being carnivorous or insectivorous ; but their 

 larvse are generally extremely voracious, and will devour almost 

 any kind of soft animal matter. This section includes the Flies 

 strictly so called, the Bot-flies, and many other tribes. The first 

 family, that of SYRPHID^E, bears an extremely close resemblance 

 to the Humble-Bees and Wasps, in the nests of which some 

 species among them deposit their eggs ; this resemblance is evi- 

 dent in the accompany- 

 ing figure, which repre- 

 sents the Eristalis, or 

 Drone-fly (A), and the 

 Anthophora retusa, or 

 Spring Wild-Bee (B), 

 two insects which differ 

 entirely in their habits, 



FIG. 428. DRONE-FLY AND SPRING WILD-BKB. 



the former being the 



very personification of luxurious idleness, doing nothing but sip 

 the nectar from the brightest flowers and bask in the sunshine 

 on the leaves, whilst the latter toils all day long, either in the 

 construction of the nest, or in provisioning it with pollen paste. 

 The wisdom of the Creator has provided the insects of the former 

 group, as a check upon the too great increase of the latter ; for 

 the larvae of the Syrphidse, when hatched in the nests of the 

 Bees, destroy their larvae, and live at their expense. Some 

 species restrain, in a similar manner, the excessive multiplication 

 of the Aphides. The perfect insects feed almost solely upon 

 flowers, preferring those of the Compositac ; and they delight to 

 hover immov.eably over certain spots, to which they will return, 



