TRANSFORMATIONS OF THE LOCUST MITE. 



309 



to two inches beneath the surface and in a slightly agglutinated mass, 

 which, however, easily becomes scattered upon disturbance of the soil. 

 From these eggs, in due time, there hatch little orange mites (Fig. 39, &), 

 which differ from the parent in having but six legs. The six-legged 

 form belongs to Latreille's genus Astoma, erected when naturalists had 

 no suspicion that it was purely a larval form. The specific name locus- 

 iarum was first proposed for it by B. D. Walsh,^** but Dr. Le Baron 

 afterward gave it the name of Atoma gryllaria^'^ in connection with a 

 detailed description. 

 Active when they first hatch and impelled by instinct, these little six- 



Fig. 39.— Trombidium locustarum.— a, female witli her batch of eg:gs (after 

 Emerton) ; &, newly hatched larva— natural size iDtlicated by the dot within 

 the circle ; c, egg ; d, e, vacated egg-shells (after Eiley). 



legged specks crawl upon the locusts and fasten to them, mostly at the 

 base of the wings or along their principal veins, just as a tick fastens 

 to a dog or a sheep, or to man. Thus attached to their victim, they suck 



Fig. 40 — Trombidium locustari>m.— a, mature larva when about to leave the wing of a locust; h, 

 pupa ; c, male adult when just from the pupa ; d, female— the natural sizes indicated to the right ; e, 

 palpal claw and thumb ; /, pedal claws ; g, one of the barbed hairs ; h, the striatiojjs on the larval skin 

 (After Eiley.) 



its juices and swell until the legs become invisible. It is in this condi- 

 tion (Fig. 40, a) that they are most often noticed, presenting to the ordi- 



^0 Practical Entomologist, i, p. 126. 



* Le Baron's Second Hlinois Eut. Report, 1872, p. 156, The author employs the term Atoma, which, 

 though at first employed by Latreille, is corrected to Astoma ih his Genera Crustaceorum et Insect- 

 orum, i, p. 162 (1806). 



