240 



EXPERIMENTAL FARMS. 



to their unusual numbers. Mr. J. H. Vivian, of Toronto, reports a remarkable occur- 

 rence of Hair-worms in Toronto, as follows : — " October 14. — On the occasion when I 

 first saw them there were millions of them both white and dark-coloured. I have a 

 large garden, and it was almost impossible to find a space of two inches between the 

 spots occupied by these worms. A very heavy rain fell on the night preceding. The 

 special peculiarity about them to me was their snake-like movements ; standing almost 

 on their tails, they swayed the upper two inches of the body in the air." 



During the past autumn they were very abundant, as could frequently be seen on 

 sidewalks where crickets and grasshoppers had been crushed. Sometimes as many as 

 five specimens were found inside a single host. There is no doubt that these parasites 

 materially affect the increase of the insects which they infest, but the statement that 

 grasshoppers so infested never lay eggs is not always at any rate correct. In October 

 last I found a female of th<^ Two-striped Locust which had been trodden upon while 

 laying her eggs betvveen two boards of the sidewalk ; upon pulling her abdomen from 

 bet veen the boards, I found she had laid five or six eggs and the abdomen contained 

 several more ready to be laid, and also one specimen of Gordius and two of Mermis. 



The Locust Mite. — The parasite of grasshoppers which has prcjbably been most 

 frecjuently noticed and which has been very widespread during the past summer, 

 is the small red mite, Tromhidium locustarum, Riley, which, in its larval form, 

 is often a conspicuous object on the bodies of grasshoppers. The larvje are small, 

 bright red, bag-like, six-legged mites (Fig. 10a.), most frequently found attached, 



"^^V 



■^ "^a/t 





\\-~ 



a, mature larva when about to leave the wing of a locust ; h, pupa ; 



Fig. 10.— Locust Mite ; 



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

 e, palpal claw and thumb ; /, pedal claws ; g, one of the barbed hairs ; h, the striations on 

 the larval skin. (After Riley.) 



in varying numbers, on or near the base of the wings of the perfect grasshoppers, but 

 also sometimes abundant on the pupte. When full-grown, these are about one-twentieth 

 of an inch in length and about half as wide. The life history of these useful allies, 



which, although so small, 



destroy many injurious lo- 



v^^ '-ssL/fw^sss- ; 7^ ''ViAM/ >==t ^ custs, has been worked out 



tl>^i^- ' J\L sJ^^XjmS.lf h^ „ fully by Dr. Riley. The eggs 



are laid in spring in clusters 



of between 300 and 400, 



an inch or two beneath the 



surface of the ground. From 



these eggs hatch little orange 



red mites (Fig. 116.), which, 



being very small, crawl out 



easily between the particles of 



, ^■'-•y' the soil and fasten themselves 



Locust Mite : a, female with her batch of eggs (after' Em^r- to their future hosts, generally 



son); b, newly hatched larva— natural size indicated by the dot selecting a spot near the base 



within the circle ; c, egg ; d, e, vacated egg-shells. (After RUey.) of the wings from which they 



Fig. 11 



