S A MANUAL OF DANGEROUS INSECTS. 



they Jiave becomo serious pests to agriculture. Tliere are a number of four-legged 

 blister mites of great importance and yet so small that they can only be seen with a 

 very high power lens. 



BARKBEETLES (SUPERFAMILY SCOLYTOIDEA: FAMILIES IPID^, 

 SCOLYTOPLATYPODID.*, SCOLYTID^, AN^D PLATYPODID^). 



All of the bark beetles, ambrosia battles and other members of this family are 

 more or less injurious to tree growth, forest products, tree seeds, fruits, etc., and 

 species known to bo injurious must be carefully guarded against. These beetles 

 are small, cylindrical with elbowed and clubbed antenna?. The head is without 

 or with very short beak and the subraentum is without a gular peduncle. In Ipidae 

 and Scolytidae (Hopkins'.s classification) the first joint of the tarsus is shorter than the 

 others combined, while in Platypodidte the first joint is as long or longer than the 

 others. They all bore in the plant tissue to deposit their eggs and their burrows 

 or galleries are characteristic of groups, genera, and species. The food consists of 

 plant tissue except in the ambrosia beetles where it consists of so-called ambrosia 

 fungi. Genera Insectorum has issued a fascicle on Ipid9B=Superfamily Scolytoidea 

 of Hopkins,' with catalogue of species of the world. 



BEAN WEEVILS (MYLABRIDiE— BRUCHIDJi:, LABIID^). 



The seed weevils or bruchid;^ brood almcst entirely in the seeds of plants, especially 

 of tho'bean and pea family. They are uniformly injurious and .should 1)0 excluded. 

 These beetles are usually small and either oval or elongate, with the head carried in a 

 downward position and with the anteniue often iJectinate or plumose. The elytra do 

 not conipletoly cover the abdomen. A catalogue of the Mylabrid;i3 (Bruchidic) has 

 been issued by Junk. 



CUTWORMS; ARMY WORMS (NOCTUID^). 



Several species of cutworms and army worms have already become world wide in 

 their distribution through their strong flj'ing ability and by commerce. As the larvse 

 are very generally destructive and not at all exclusive in food habits, they need to be 

 carelully guarded against. Lar^■oe may bo transported anywhere on the ships. Cirphis 

 imipuyicla ITaworth, the army worm; Spodoptera mmintia Boisduval, the grass army 

 ■worm, and Agrotis ypsilon Kottonburg, the greasy cutworm, are practically co.s- 

 mopolitan. A discussion of most of the injurious species will be found in Sorauer's 

 Handl)uch dor Pflanzenkrankheiten, 3d od., 1913, vol. 3, pp. 348-374. 



WEEVILS. RHYNCHOPHORA— COLEOPTERA. 



The oxp(>rioncc of the last few ^^ears in the quarantine of horticul- 

 tural products has shown that one of the groups most hkely to intro- 

 duction is the group of weevils which comprise a large section of the 

 order Coleoptera. 



Owing to the development of nnin}' species of weevils in the roots, 

 stems, and fruit of almost evt^r}^ type of plant known, it is very easy 

 to introduce them in immatm-e stages in such a manner that they may 

 take hold and attack the introduced plant. Owing to the necessity 

 of determining practically all of the weevils introduced by a search 

 through foreign literature a majority of the species so far introduced 



'ToLh. Scries 17, pari 11, Hurouii of Knlomology, U. S. Dept. of Asric, lOlo 



