THE DESERT COEN PLEA-BEETLE. 



Fig. 4.— The desert corn flea-beetle: 

 Prepupa. Greatly enlarged. 

 (Original.) 



partially covered with short stiff hairs. In color and texture they 

 are so much hke the corn roots in which they are found feeding that 

 one will often overlook a larva, even with the aid of a microscope. 

 However, when quite numerous, the full- 

 grown larvae are easily found on the roots 

 of a com plant or in the surrounding soil. 



The full-grown larvse just previous to 

 changing to prepupse are often as much as 

 o mm. (three-sixteenths of an inch) long, 

 varying from 3.5 to 5 mm. in length; the 

 average length being about 4 mm. They are opaquely white in color, 

 well segmented, and cyhndrical in form as compared with the younger 

 larv£e. 



THE PREPUPA. 



The prepupa (fig. 4) is the full-grown larva which has shrunken 

 preparatory to pupation, and is thus reduced to about one-half its 

 former length, though it is considerably greater in 

 diameter. It usually lies quietly, in a curved position 

 resembling in shape a question mark. It is segmented 

 and of the same texture as the full-grown larva. 



THE PUPA. 



The pupa (fig. 5) very closely resembles the adult in 

 size and appearance. It varies from 1.5 to 2 mm. in 

 length and from 1 to 1.3 mm. in width. It is white 

 when first formed, and has aU appendages firmly com- 

 pressed against the body. It is quite delicate, soft 

 bodied, and sparsely covered with fine hairs. 



Fig. 5.— The desert 

 com flea-beetle: 

 Pupa. G r e a t ly 

 enlarged. (Origi- 

 nal.) 



LIFE HISTORY AND HABITS. 



THE LIFE CYCLE. 



The totariength of the life cycle of this beetle in the Southwest 

 averaged 46.3 days, with a minimum of 31 days in July and a maxi- 

 mum of 79 days in March, April, and May. This, of course, is subject 

 to variation as in the case of most insects, and depends upon prevail- 

 ing meteorological conditions. 



The average length of the combined egg, larval, and pupal stages 

 (Table I) of 82 specimens averaged 37.5 days for all temperatures, 

 varying from a minimum of 24 days in June to a maximum of 65 days 

 in March. Adding to this the average time required for the female 

 to compl(!to bor development after issuing, before sIk^ deposits eggs, 

 namely 0.8 days, gives the a})ove-mentione(l Icngtli of 46.3 days for 

 the complete life cycle. 



