INSECTS PREYING ON THE ORANGE APHIS. 



183 



THE FOUR- SPOTTED APHIS-FLY.* 



(Baccha babista Walker.) 

 [Figs. 81, 82 and 83.] 



This is a rather slender fly, with a large, well-rounded head, and a 

 club shaped hind body, supported on a slender stalk or peduncle; the 

 eyes, which cover the greater part 

 of the head, are mahogany -brown; 

 the thorax black, with a metallic 

 luster, and with a golden-yellow 

 shield ; the wings are transparent; 

 the clab of the abdomen brown, 

 marked with four pale triangular 

 spots. (Fig. 81.) Length, 10 mm 

 (A ich). 



FIG. 82. Baccha babista, larva. 

 (Original.) 



FIG. 81. Baccha babista, adult. (Original.) 



The larva (Fig. 82) has a cylindrical body, ^greenish, with a longitud- 

 inal band of dull red on the back; the joints, about equal in size, ex 

 cept the first three, which are tapered, and form a re- 

 tractile neck ; the surface is covered with very short, 

 stiff hairs, giving it a velvety appearance ; each joint 

 of the body is armed with a row of soft spines above 

 and a pair of fleshy prop legs below.Length, when at 

 rest, 7.5 min (-^ inch). 



The puparium, or chrysalis (Fig. 83), has the form 

 of a cone, with one side flattened and fastened to the 

 surface of the leaf; the large end is broadly rounded, 

 convex; the color varies from dirty white to dull yel- 

 low, and there are more or less distinct cross-shaped 

 markings upon the back; the spines of the larva shrink 

 to minute prickles on the puparium. 



The eggs are elongate-oval, brilliant white, the surface marked 

 with diamonds by obliquely intersecting engraved lines. They are 

 deposited by the parent fly singly upon the leaves among Plant-lice. 



Parasites. Minute Chalcid parasites prey upon the Syrphus larva, 



FIG. 83. Baccha ba- 

 bixta, puparium: 



a, doi'8Jil view; 



b, lateral view. 

 (Original.) 



* This very common species has been described by Mr. Ashinead under the name 

 Conopsl quadrimaculata. (Orange Insects, page 69.) 



