72 



in Massachusetts. He found it on rose bushes in his garden where it was busily engaged 

 devouring plant lice. It is of a scarlet red colour. 



The Grasshopper Parasite (Trombidium gryllarium). 



As in other classes of insects, mites furnish us with friends as well as enemies. 

 In this instance we find an ally who carries on war against the grasshoppers. Harris, 

 in his " Insects Injurious to Vegetation," page 191, draws attention to the fact 

 that locusts in the Eastern States " are much infested by little red mites ; these so 

 much weaken the insects by sucking the juices from their bodies, as to hasten their 

 death. Ten or a dozen of these mites will frequently be found pertinaciously adhering 

 to the body of a locust, beneath its wing-covers and wings. A mite similar if not iden- 

 tical has been found at work among the swarms of locusts which inhabit 

 the Western States. It is described by Dr. Le Baron in his first Report 

 on the Insects of Illinois, in 1872. Figure 59 represents it in the larval 

 condition. They are red, about one-thirtieth of an inch in length, and are 

 found chiefly on the under side of the basal half of the under wings where 

 they adhere so firmly that it is difficult to scrape them off with a pen-knife. 

 The mite so attached soon swells so much that its six small legs, quite visible 

 at first, become almost invisible, lost in the swollen body. These little 

 mites help much to reduce the numbers of the destructive locusts ; they 

 suck the bodies of their victims until they beeome exhausted and die. 



Fig 59. 



Trombidium Sericeum. 



This species ffig. 60) in also red. It has been found devouring the eggs of the de- 

 structive locusts in Iowa and Minnesota, creeping into the holes in which the eggs have 

 been deposited and devouring their contents. 



During the winter of 1878 an undetermined species of Trombidium 

 was observed by me devouring the eggs of the moth of the forest tent 

 caterpillar. On examining some egg clusters one evening under the 

 microscope it was observed that at some points the glutinous coating 

 which covers the clusters was imperfect, that a piece here and there had 

 disappeared leaving the eggs bare, and in some cases some of the ex- 

 posed eggs were empty. On cutting into the clusters they were found 

 to be colonized by mites. The outside gummy matter is of a sufficiently 

 porous texture to afford shelter to these little friends, who had evidently 

 eaten into the eggs and devoured the young larvae, and had also con- 

 sumed the missing portions of the gummy covering. In the range of 

 of an egg-mass some eggs would be found uninjured, while from others there would pro 

 ceed several (in some instances as many as five) active little mites, who, when thus dis 

 turbed, would run in and out of their dwelling places, at the same time keeping up a 

 peculiar drumming motion with their tiny antennae. Besides the smaller, younger speci- 

 mens, four or five of which could find ample room and to spare within a single egg shell, 

 there were other larger specimens apparently of the same species, but more mature. 

 These were of a pale red colour, with bright, red eyes, more sluggish in their movements, 

 and one such specimen would nearly fill an egg. On the outside, clusters of pale red eggs 

 were found, supposed to be the eggs of these mites. 



On almost every egg-mass examined some of these mites were found, and if they 

 are thus generally distributed over the whole area inhabited by these moths they must 

 prove a very efficient check to the' undue multiplication of the species. There are mites 

 also which prey upon the eggs of the oyster-shell bark louse, and on those of the canker 

 worm. 



Among other families of mites may be mentioned the 



single section 



Snouted Mites (Bdellidce), 



the fresh water mites, most of whom live on water insects, there are also some species of 



