14 BULLETIN 737, U. S. DEPARTMENT OF AGRICULTURE. 



SPECIFIC CHARACTERS. 



Median region of epistoma with a row of five seta; on each side, lateral 

 regions naked; labruin with about seven straight setae on the upper surface at 

 each anterior corner, several long, inedianly curved seta? along the anterior 

 margin and an oblique row of three, shorter, stouter, hook-shaped setse on the 

 under surface on either side of and posteriorly approaching tbe median line; 

 clypeus naked; stipes labialis, mentum, and submentum with long soft setse ; 

 maxillary articulating area not setiferous. 



LARVAL INSTAKS. 



First-instar larva 0.55 to 1.4 mm. long ; yellowish white ; the digestive tract 

 showing darker; body set sparsely with very long, pale hairs; head 0.12 to 0.10 

 mm. long. Second-instar larva about 3 mm. long; yellowish white; head 0.22 

 to 0.24 mm. long. Last-instar larva about 4 mm. long ; yellowish white ; set 

 entirely with long, silky, yellowish brown hairs ; chitinous parts brown ; 

 spiracles concolorous with body ; head 0.5 to 0.7 mm. long. 



THE PUPA. 



Pupa (PI. II, fig. 2) uniformly white when first transformed. Length (aver- 

 age) 3.5 mm. (2.5-3.75 .mm.) ; width about 1.7 mm. (1.1-2 mm.); tips of 

 elytra attaining fourth visible ventral segment of abdomen. Metathoracic legs 

 beneath the elytra not attaining tips of inner wings. Head bent upon thorax 

 and beneath pronotum. Ultimate and penultimate abdominal segments ven- 

 trally each with a pair of fleshy lateral protuberances. 



THE ADULT. 1 

 (PI. Ill, fig. 1; text fig. 7.) 



Elongate-oval, moderately convex. Uniform dull reddish yellow or brown- 

 ish red. Head broad, eyes small. An- 

 tennae rather narrow, second and third 

 joints smaller than first, the third dis- 

 tinctly triangular ; fourth to tenth 

 about as wide as long; eleventh oval. 

 Thorax strongly convex, front angles 

 acute, hind angles wanting. Punctua- 

 tion of entire upper surface fine, uni- 



FiG. 7. — The tobacco beetle (Lasioderma 

 serrieorne) : Antenna of adult. Greatly 

 enlarged. ■ form, not dense. Length 2.2 to 3 mm 



LIFE HISTORY AND HABITS. 



SUMMARY OF LIFE HISTORY. 



The life history of the tobacco beetle may be briefly summarized as 

 follows: 



In material kept constantly warm, breeding is continuous and 

 there may be as many as five or six generations in a year. Under 

 usual conditions in warehouses in the latitude of Virginia there are 

 ordinarily three or four generations a year. The beetle lives in its 

 food substances during all stages of its existence, and the time re- 

 quired to complete its life cycle depends mainly upon temperature 

 and may be as short as 45 days. Normally, in summer, the time 



1 Description of adult by W. S. Blatehley (71). 



