128 PRINCIPAL HOUSEHOLD INSECTS. 



The larva is white and of the usual ptinid form, quite similar to that 

 of the drug-store beetle, and feeds, like that species, in a little globu- 

 lar case of delicate construction and composed of the material that it 

 infests, and which it cements loosely together. The development of 

 this species is said to be annual in Europe. It has been carried 

 through all its transformations here at Washington in about three and 

 a half months, the pupal. period lasting thirteen days. 



The adult beetles are nocturnal and may be found in the dead of 

 winter crawling upon the walls of cellars and uuheated buildings. 



THE BROWN SPIDER BEETLE. 

 (P tin us brunneus Duft.) 



The last of the domestic Ptinidse that will require special notice is 

 the one above mentioned, and which, as previously stated, differs from 

 its congener chiefly in lacking the white marking on its elytra. Nor is 

 there probably any degree of difference in habits and life history 

 beyond the recorded list of food materials observed for each species. 

 Both occur in the same locations, not unusually living together in 

 apparent harmony. Like Ft. fur, it is disposed to be omnivorous and 

 is somewhat of a scavenger, frequenting cellars and attics, storehouses, 

 henhouses, and pigeon lofts, being competent to eke out a living almost 

 anywhere where anythiug animal or vegetable is stored. Among the 

 different substances that afford it sustenance are books, feathers, skins, 

 dried mushrooms, and the excrement of rats and other domestic 

 animals. It sometimes gets into drugs, and is recorded to have attacked 

 musk root and the powdered leaves of senna and jaborandi. 



SPECIES OF OCCASIONAL OCCURRENCE IN VEGETABLE STORES. 



The following insects are so often found in dry vegetable foods as to 

 deserve brief mention. Like preceding species, they are cosmopolitan 

 in distribution and occur in the greatest numbers in tropical climates. 



The granary weevil (Calandra granaria Linn.), a small dark-brown 

 species about an eighth of an inch long, is very partial to the pearled 

 barley used in the preparation of soups, and the chick-pea, a legumi- 

 nous seed cultivated for the same purpose in tropical countries. 



A similar species, the rice weevil (C. oryza Linn.), which, with the 

 preceding, is most destructive in stored grain, as an adult insect some- 

 times invades boxes of cakes, crackers, yeast cakes, macaroni, and 

 similar breadstuff's, and is said to attack chestnuts, bird seed, and even 

 to injure tobacco. It also breeds in rice and in cracked corn and other 

 cereals that are sufficiently coarse for the purpose. 



Two weevils belonging to the family Bruchidre, of wide distribution, 

 and known respectively as the pea weevil (Bruchus pisorum Linn.) and 

 the bean weevil (B. obtectus Say), lay their eggs upon ripening peas and 

 beans in our gardens and thence find their way to our tables, being 



