308 EEPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



hoppers' eggs, and also the red mite or spider that sucks them, as you will perceive on 

 examination. I trust they will be received in good order. I send them at the request 

 of A. Whitman, of Saint Paul, of this State, with whom I am corresponding some- 

 times on this grasshopper matter. — [Letter from R. B. Potts, U. S. N., Worthington, 

 Minn., August 18, 1876. 



We have received a copy of the Yankton Press and Dahotaian, of April 25, contain- 

 ing an article calling attention to the fact that a parasitic insect is devouring the eggs 

 of the locusts all over Southern Dakota. The insect is described as a ''little red bug," 

 and also as the same parasite which is found on the bodies of fully-grown and migrating 

 locusts. This is evidently a mistake, the two being entirely different insects in habits 

 and appearance. The " little red bug " is known as the " silky mite," and is described in 

 Riley's Seventh Report under the name of Trombidium sericeum. Its habit of eating the 

 eggs of the locust was reported as early as 1874. It is also described in Riley's Ninth 

 Report, which has just been issued. In the locality mentioned it is so numerous that 

 scarcely a sac of eggs has escaped, and farmers are very much encouraged concerning 

 their crops. — \_Country Gentleman, May 10, 1877. 



During the fall of 1876 reports were received from various quarters, especially the 

 southwestern counties, denoting the presence of the Silky mite in great numbers, while 

 various larvae were discovered at work upon the eggs almost everywhere. The Silky 

 mite was found to be still more numerous in the spring, sometimes so thick as to redden 

 the ground, and in localities where it had not been seen in the autumn. Of replies to 

 the inquiry of the Entomological Commission, "proportion of eggs that failed to hatch, 

 and probable cause of failure," nine out of thirteen (in Minnesota) express the opinion 

 that a large percentage (one-half or more) failed to hatch, and the cause generally 

 assigned is the Silky mite. Testimony on this point can apply with exactness to only 

 such little cases as come under each man's partioalar notice, but the replies, taken with 

 similar reports, denote that considerable* quantities of the eggs were destroyed before 

 hatching.— [Allen Whitman, Saint Paul, August, 1877. 



In conversing with a gentleman this evening, he says: "What grasshoppers remain- 

 ing here are now being destroyed by a bug, a small, * red bug,' which are now upon 

 their wings sapping the life out of them. They are about the size of a chintz bug." — 

 [E. D. Barton, Sarcoxie, Mo., July 12, 1877. 



^ The warm spell has hatched out a great number of the little silky mites. In fact, 

 many farmers tell here that the ground is red with them in places. — [A. Whitman, 

 Saint Paul, Minn., April 17, 1877. 



A reliable man from the next county to this (Emmett) informed me" that his garden 

 soil was red with the little insect often spoken of, and that they were going for the 

 eggs with a vengeance. — [John Walker, Emraettsburg, Iowa, April 17, 1877. 



I have found many red parasites on the locusts, larger ones on those in the pupa 

 state than on those that had more fully developed wings. Have found no internal 

 parasites. — [G. M. Houston, Harrisonville, Mo., June 8, 1875. 



The red parasite seems to feed more upon the indurated mucous sac inclosing the eggs 

 than upon the eggs themselves ; yet, I think, where the covering is destroyed, the eggs, 

 in most instances, do not hatch. The red parasite is the first to attack the young, by 

 depositing its eggs [young mistaken for eggs] upon them. I have seen so many of 

 these upon young locusts that they sucked all the vitality out of them. — [J. G. McGrue, 

 Audubon, Minn., June 20, 1877. 



There is some insect that appears to deposit small red eggs, from one to a dozen or 

 more, under the wings of the grasshoppers. I have seen them in large masses, and 

 have found them on those with their wings just starting. I find, also, that at least 

 nine-tenths of the full-fledged ones have them, and that they are dying all the time in 

 great numbers in consequence. — [G. Z. Craig, Diamond City, Jasper County, Missouri. 



In spring, the female lays between 300 and 400 minute spherical, 

 orange-red eggs in the ground (Fig. 39, a). They are usually from one 



