238 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



OBSERVATIONS ON WINGLESS MAY BEETLES 



By R. A. ViCKERY and T. S. Wilson 



During the spring of 1918, from April to July, this station received 

 many reports of damage to crops by the wingless May beetles. Two 

 species were injurious, namely, Lachnosterna cribrosa and Lachnosterna 

 farcta. The former was reported to be injurious to cotton in Bexar 

 County and in other counties in southern Texas, and to wheat in 

 northern Texas. The latter was reported to this station only from 

 Bexar County, the most serious damage being done in and near the 

 city of San Antonio. Both species are very destructive to crops when 

 they occur in large numbers, as they attack young plants and may 

 completely destroy all plants in a large field. Furthermore, they 

 remain numerous long enough to destroy several plantings. 



Lachnosterna cribrosa is about one inch long, shiny black in color and 

 wingless. Lachnosterna farcta is about the same size but brown in 

 color. The latter species has wings but they are too small to be 

 used in flying. Both species have stout clumsy bodies with distended 

 abdomens. 



These beetles remain in the ground during the day and emerge only 

 at night to feed. Lachnosterna cribrosa comes out about sundown and 

 remains out for several hours but L. farcta comes out after dark and 

 remains out a longer time. Both species are energetic travelers and 

 may be seen wandering about after dark. Their choice of food is 

 limited by their clumsiness and inability to fly, so that they eat almost 

 any vegetation that they can reach. They seem best able to climb 

 plants having small round stems, such as young plants of cotton, 

 bean, Amaranthus, and alfalfa. They usually do not chmb high upon 

 the larger plants but feed on the more accessible lower leaves. Both 

 species feign death when disturbed. 



In the laboratory these beetles were kept in uncovered wooden 

 boxes 30 inches in length, 16 inches in width, and 12 inches in depth, 

 and they were seldom able to climb out. Lachnosterna cribrosa began 

 to emerge from the soil in these boxes about 6.30 p. m., sun time, and 

 had all reentered the soil by 9.30, but L. farcta was still emerging at 

 this hour. 



The beetles burrow into the ground to a depth of from four to six 

 inches. They usually enter near the base of the plant upon which 

 they have been feeding. Many often enter near the base of one plant 

 or of a small cluster of plants and they kick up a small mound of pul- 

 verized soil, giving the characteristic appearance as shown in figure 3, 

 plate 13. The emergence holes are round and about one-half inch in 



