GRASSHOPPERS AND OTHER INJURIOUS INSECTS OF 1911 AND 1912. 39 



of grasshoppers, but not materially. The method of egg laying makes it 

 difficult for the tiny larva to find an egg pod and when it does, each lax'va 

 destroys only one pod and not always the whole of that. Their destruction to 

 crops offsets the good they do in destroying grasshopper eggs. Only one case 

 of injury (by the beetle) to a crop, flax, was reported this year, (1912), but 

 the injury was so early that the flax was able to recover aiid mature a good 

 crop of seed." 



Trombidium sp. This red mite is another interesting enemy of 

 the grasshopper, but we have always beheved that too much impor- 

 tance was placed upon its services by our farmers, for we have 

 personally observed many female grasshoppers ovipositing in late 

 summer, although loaded with these parasites. It is in spring, then, 

 when in the bright scarlet mature form, that it does its best work, 

 consuming many grasshopper eggs and thus reducing the numbers 

 of the pest. We quote from both Mr. Somes' and Mr. Howard's ob- 

 servations in 1911 and 1912. 



"Our studies of the parasites of grasshoppers naturally began with 

 Trombidium, the 'red mite' or as it is more commonly called 'the red bug.' 

 There can be no doubt that this mite has a very decided economic value in its 

 work against the grasshopper, but contrai-y to general opinion this really 

 effective part of its work is accomplished early in the spring rather than in 

 midsummer when it is so commonly observed. In my preliminary examination 

 of the field early in May I found this mite present wherever I found grass- 

 hopper eggs in abundance and very frequently observed it actually feeding on 

 the eggs. It is evident that every egg thus attacked means one less grass- 

 hopper to hatch. As regards the actual beneficial effect of the mites later in 

 the season we are inclined to think that these are over-estimated. It has been 

 frequently observed that grasshoppers bearing from several to twenty or more 

 of these parasites still feed and appear normal in all their functions. In some 

 cases where there has been very evident damage to the wings and even to the 

 dorsum of the basal abdominal segments the hoppers appeared undisturbed in 

 vigor or in appetite. When the hopper moults it frees itself from the mites 

 but more or less of these soon become again attached to it. From our observa- 

 tions it appears that the really beneficial stage of Trombidium is the adult in 

 early spring rather than the more numerous and conspicuous young in summer. 



In our early examinations of the eggs we found small coleopterous larvje 

 associated with the Trombidium in the vicinity of masses of eggs. Through 

 error these were not reared but they were doubtless Meloids and in all prob- 

 ability belonged to the genus Epicauta." Somes 1911. 



"Trombidium was very abundant everywhere I collected. Early in the 

 summer engorged females were found in egg pods of grasshoppers in the soil. 

 They apparently feed on the eggs of any grasshopper without distinction. By 

 May 27th eggs of Trombidium were found in the soil and a life history study 

 was begun. This will not be complete until next summer, so the details, all 

 of which should be verified by another season's observations, are not given 

 here. The Trombidium, while it does some good in checking the grasshopper 

 plague, is not what has been claimed for it in the past. They do destroy some 

 eggs, but at the most two or three eggs only are required for the engorgement 

 of an adult, and a lesser number for the immature forms, so that only a small 

 percentage of eggs is destroyed. The larval forms apparently do very little 

 harm to the nymphs and adult grasshoppers. I have seen nymphs with thirty 

 to forty engorging larvae of Trimbidium going on successfully with their 

 transformations." Howard 1912. 



