113 



whether the red hirv;e of tlie Plilceotlirips are larvie of Oecidomyia. 

 The Thrips is ahiiost constantly to he found in ch^ver lieads and it is 

 perhaps not strange that ])ersons unused to separating different kinds 

 of insects, in h)okin<>' for minute species in Clover heads, should be de- 

 ceived by these little creatures, consi^icuous from their numbers if not 

 from their size. 



The JassidjB, oc(*urring upon grasses, have been present in their usual 

 abundance, and liave been watched during the season especially to de- 

 termine important stei)S in their life-history. The first point which it 

 was our effort to determine was as to the method of hibernation. 

 Adults of Deltocephalus inimicus and dehilis and AgalUa sangiiineolenta 

 had been taken in sheltered locations last season up to the time that 

 winter actually set in, and with the opening of spring search was at 

 once begun for them in such places as they were most certain to ap- 

 l)ear. The only species found, however, was AgalUa sangiiineolenta^ and 

 no specimens whatever of Deltocephalus were found. Search for adults 

 began March 8 and continued till larvae appeared all over grass land, 

 aiul had adults been present they could scarcely have escaj)ed notice. 

 This seemed to show pretty fully that eggs must be deposited in fall 

 and that the adults j^erished during Avinter if not in late autumn. To 

 determine more certainly the place of deposition of eggs and whether 

 adults could possibly survive the winter to oviposit, a pen was made 

 about G by 10 feet in size, inclosed by boards placed close together and 

 set down into the ground, 2 feet in height, and with all cracks or open- 

 ings closely stopped, but open above to sun and rain. This was carefully 

 examined to make certain of the absence of the adults and repeatedly 

 searched to make sure of any introduction of Jassids. Larvae from 

 without could not possibly enter, as they can jump but a few inches 

 from the ground at best and very little when first hatched, while the 

 possibility of adults getting into this inclosure, even if any had been 

 found in any place, were very slight indeed, and any such would have 

 been found in the frequent examinations of the pen. As soon, how- 

 ever, as larvae appeared over grass lands in general, and they appeared 

 in millions within a few days of the time that the very first were found, 

 this inclosure also contained larvaj in numbers. The proof therefore 

 seems conclusive that larvae hatch from eggs that have been deposited 

 in the grass in the autumn or early winter preceding. 



The first larvt^e were seen April 23 in grass on the south side of one 

 of the college buildings, but had not appeared elsewhere, nor did they 

 appear in great numbers till May 12, evidently beiugretardedby cold and 

 wet weather. The larvae taken Ax)ril 23 were nearly black in color and 

 developed into i). inimicus^ one adult being secured June 29. Larvae 

 of the same species of later broods are usually much lighter colored, 

 almost whitish, with occasional individuals of darker color, and after 

 first or second moult all present a characteristic marking, consisting of 

 a black lateral margin to thorax and abdomen. Larvae of B, inimicus 



