136 
other allied species, which are somewhat boreal in their habits, can 
withstand a great degree of cold, is undoubtedly true, but they are 
certainly affected by sudden and considerable changes. 
Insects and otfur animals that prey upon them. —The foes, especially 
cf the same sub kingdom, to which they belong, are numerous and 
often assist greatly in diminishing their numbers. At present I shall 
Fig. 25. only call attention to the more important of these tiny aids. 
The Locust-Mite, (Trombidium lodustarum) is one of the 
most efficient aids in keeping the locusts in check belong¬ 
ing to the invertebrate division. It is the same mite that 
Dr. LeBaron described in his Second Report as Atoma 
yryllaria. But his description rebates only to the prepar¬ 
atory state, in which it possesses only six legs; the perfect 
Young - form, as is the case with all (except possibly a very few 
Locust- Mite, species) mites, possesses eight legs. 
When first hatched it is of an orange, or pale reddish color; ovoid 
in form with six comparatively long and apparently cumbersome legs; 
it is then very minute. When it reaches in the process of growth 
what may be called the full-grown larval state, it is very different in 
form; it is now more elongated and cylindrical, with two transverse 
constrictions; to use a rather ludicrous comparison, it resembles a 
microscopic potato. When it has reached the perfect state, it is of a 
deeper red, varying from orange red to scarlet. It is somewhat trian¬ 
gular in form with the angles rounded; being broadest in front and 
narrowing to the rounded posterior extremity, thickly covered with 
short hairs; and eight, legs. The male differs from the female in being 
shorter, and comparatively broader in front. 
Scientifically the species is distinguished by the following characters: 
“By the papal claw consisting of one large hook, with a second 
smaller one originating from its middle, and three stout spines from 
near its base, and by the thumb being of uniform diameter, armed 
with rather long hairs terminally, and reaching to or very little be¬ 
yond its tip; also by a sunken, polished plate at the end of the body, 
dorsally.” 
In the perfect state this mite lives in the ground, subsisting on 
such food as it can find that is appropriate, especially insect eggs and 
probably minute larvae. It sometimes proves quite destructive of lo¬ 
cust eggs, of which it appears to be very fond. In its larval state it is 
chiefly found on grasshoppers, attached to the back immediately under 
the base of the wings, or along the larger veins of the wings near' 
the base. 
As shown by the First. Report of the IT. S. Entomological Com¬ 
mission there are quite a number of insects that in their perfect or 
Fig. 26. preparatory states prey upon locust (grasshopper) eggs. 
Among these are two or three dipterous larvae; several 
ground-beetles and their larvae; the larvae of meloe, and 
some of the Blister-beetles ( Epicenta ); and the larva of a 
II vmenopterous species. 
In the same report quite a number of species that prey' 
upon the Acrideans while the latter are in the young or 
perfect state, are described. These include a number of 
our Tiger and Ground-beetles; several species of Asilus- 
BlistcrBeetle, fl es (Dipterous insects), vhich are long, slender-bodied 
flies of large size; several species of large wasps. But the most effi- 
