c 



2 BULLETIN 422^ U. S. D^f^,:^T3y|:i3NT OF AGRICULTURE. 



DESCRIPTION. 



The egg (fig. 1) is ellipsoidal in shape and creamy white when first 

 deposited, later becoming brownish. Ten eggs gave an average 

 length of 1.24 mm., ranging from 1.16 to 1.30 mm., and an average 

 width of 0.67 mm., ranging from 0.62 to 0.76 mm. 



THE FIRST-STAGE LARVA. 



The general color is greenish white, with light, dirty brown head, 

 and with the tips of the mandibles and the claws dark brown. The 

 head and legs are large and out of proportion to the rest of the insect. 

 The surface of the body is sparingly covered with short spines. Six- 

 teen pairs of branched appendages extend from the sides of the body, 

 the branches being larger on the anterior pair. Another pair of long 

 appendages originates on the dorsal surface of the body, just anterior 

 to the anus, and it is upon this pair that the excrement and cast skins, 



commonly known aS the ''pack," are carried, the pair 

 )t^".T.'^^^v. of appendages sometunes being called the ' ' f secifork." 



The length of the first-stage larva, includmg the head, 



is about 1.5 mm. and the width of the head about 



0.46 mm. 



THE SUCCEEDING LARVAL STAGES. 



There are in all five larval stages. The principal 

 difi^erence between them is the increase in size after 

 — "•'^ each molt, the full-grown larva measuring from 5 to 



ftg. i.-Eggpiant tor- 55 ^im. in length. 



toise beetle ( Cassida „, . . , . • , 1 • , • /. , t 



-paiiiduia): Egg. ihcre IS some variation m the position oi the ap- 

 Greatiy enlarged, peiidages aloug the sidcs of the body in the various 

 ^" ' stages. After the first molt the head and legs are 



smaller in comparison with the growth of the body and are not so 

 conspicuously out 'of proportion as in the first instar. The color 

 of the body in the second and in the succeeding stages is light green, 

 sometimes tinged with yellow. The cast larval skins of the various 

 stages are often retained on the fsecifork up to the time the larva is 

 ready to transform to the pupa. They are arranged consecutively, 

 that of the first nymphal stage nearest the tip of the fork and with the 

 head molts on the upper surface of the pack as it is held over the 

 dorsal surface of the body. 



The width of the heads of individuals in any one stage is quite 

 constant, that of the second instar being about 0.55 mm., that of the 

 third about 0.67 mm., that of the fourth about 0.82 mm., and that of 

 the fifth about 0.97 mm. 



THE PUPA. 



The fringe of appendages persists in the pupa, there being five 

 branched pairs on the sides of the abdomen and about 45 smaller 

 appendages around the edge of the prominent thoracic shield. The 



1 



