130 The Rocky Mountain Locust. 



short and slender, projecting but little beyond the outline of the 

 body. They are 6- jointed [in reality they are but 5-jointed, the 

 middle joint much the shortest, and the terminal joint longest. — 

 c. v. k. ], garnished with short stiff bristles, and terminate in two 

 slender, curved hooks. The anterior and middle legs are closely 

 approximate and situated near the anterior extremity of the body ; 

 the posterior are set a little nearer to each other, and a little in ad- 

 vance of the middle of the body, being inserted at the posterior part 

 of the anterior division or lobe. Four hairs project from the pos- 

 terior extremity of the body. 



The dorsal figure just given (Fig. 30,) ex- 

 hibits the general appearance of the mite 

 under a high magnifying power, and figure 

 31 which represents a ventral view of the mite 

 found on our house-flies, and which is doubt- 

 less the A. parasiticum of Latreille, will 

 better show the structure of the head and 

 a stoma, parasite legs. During some seasons scarcely a fly can 

 of the House-fly. ^ caU ght that is not infested with a number 

 of these blood-red mites, clinging tenaciously around the 

 base of the wings. 



The genus Astoma (and the same is probably true of 

 most other six-legged genera) is only the larval or imma. 

 ture form of some other mite ; and this very Locust Mite 

 may be the larva of the Silky Mite previously described, 

 for aught we know to the contrary — so much is there yet 

 to learn of the transformations of the mites. Indeed, 

 Hermann, and some other arachnologists have actually 

 referred Astoma to Trombidium. In speaking of the Irri- 

 tating Harvest Mite (JOeptus irritans, Riley, 6th Rep., p. 

 122) — the so-called Jigger of the Mississippi Valley, which 

 is, in all probability, also an immature form — I have stated 

 my belief that its normal food must, apparently, consist of 

 the juices of plants, and that "the love of blood proves 

 ruinous to those individuals who get a chance to indulge 



