INSECTS PREYING ON THE ORANGE APHIS. 



185 



Fi(5. 85. —The 

 Priiinoae 

 A p b i 8 ■ fi y, 

 larva. (Oiij;- 

 iuul ) 



Larva. — Tho mnjijiot has tlio form and smooth surface of 7>. Jugcns, 

 but is more transparent and lighter iu color, yellowish-green and white 

 predominating. 



THE PRUINOSE APHIS-FLY.* 



[Figs. 85 and 86.] 



A very common enemy of the Orange Aphis is a small two-winged 

 fly. Its young is a greenish, slug-like maggot, 3""" ( j'^i,- inch) in length ; 

 the body is flattened beneath, convex above, with two deep longitudinal 

 furrows on the back; the joints of the head and neck are 

 small and tapering, as in the larva of Syrphus, and can be 

 greatly extended or entirely withdrawn into the body; the 

 body behind is rather broadly rounded ; from the upper 

 surface near the hind margin arises a i)air of diverging 

 appendages like the horns of a snail ; the ends of these 

 appendages are open pores, and the apparatus constitutes 

 the principal spiracles, through which the animal breathes; 

 the surface of the larva is roughened with minute knob- 

 like excrescences. 



When ready to transform into pupa, the larva glues it- 

 self to the surface of the leaf by means of a black gum. 

 The body of the larva shortens and thickens, becomes oval 

 iu shape, and assumes a golden-brown color, the breathing tubes are 

 now very i)romineut, the lateral furrows of the larva are not obliter- 

 ated, but divide thepuparium into longitudinal lobes, and appear as 

 broad ban«ls of darker color upon the surface of the casket. 



When vacated by the fly the puparium splits in a ring near the an- 

 terior end, releasing the tip in the form of a conical cap the cap also 

 sjdits across the middle, dividing into 

 two valve-like halves, only one of which 

 is usually throwu off by the flj' in its 

 exit. 



The fly (Fig. 86) is a small, thick 

 bodied insect, about 2""" (yf^ inch) in 

 length, with deep purple eyes, transpa- 

 rent wings, and particolored legs; the 

 body is bluish-white (pruinose), with 

 sx^arsely placed black hairs ; the upper 

 surface of the thorax is marked with 

 four longitudinal stripes of umber- 

 brown. The egg is white, elongate oval, with tine longitudinal lines; it 

 is fastened to the surface of the leaf among the living Aphis. 



Transformations. — What has been said of the habits and trausforma- 



Fir.. 86.— The Pruinose Aphis-fly. 

 inal.) 



(Oiig- 



* Dr. S. W. Willistoti writes concerniiij^ this specii-s: "They are eyideutly An- 

 tbomyids, Imt I cannot place them in any of the Eiiiopean genera. I am ac(inaintod 

 with a nunibor of the Anthomyid genera, but this species dift'ers from any I know iu 

 thtj few bristles ou the bead and face." 



