ECONOMIC ZOOTXXtY KN'rf)MOT.0GY. 59 



conio out early in July — from the Ttli to (ho lltli of that luouth, according to our 

 experience — and the last emerge in Octoher, or possibly in November. 



" From solitary queens brought in from the field April 2G to May 3, 1906, and 

 kept in the insectary under natural conditions, the first eggs were obtained May 

 8, 9, 10, and 15, and the first larvse from these eggs June 4. The length of the 

 egg stage in the various lots deposited by these females varied from 22 to 28 

 days. The larviB began to pupate about the middle of June, the larval period 

 being, in four cases, IG, 17, 19, and 23 days. The first adult appeared in this 

 cage July 7, and others emerged at intervals throughout the remainder of the 

 year, the pupal stage averaging about 18 days. Judging by these data, the time 

 from the deposit of the egg to the appearance of the adult is approximately 2 

 months. ... 



•' The process of growth and multiplication are interrupted by winter, dur- 

 ing which the ants hibernate in a dormant state in whatever stage they hapiten 

 to have reached, resuming their activities in spring at the point where cold 

 weather arrested them. The workers open up the nests to the surface, usually 

 in late March or in April, the evidence of this beginning of their seasonal activi- 

 ties being the appearance of circular heaps of minute pellets of earth around 

 the months of their burrows." 



A table is presented which shows the number of ants in all stages contained 

 in 20 nests dug out in an oat field on August 28, 1906. In fully developed nests 

 the number of ants in the various stages varied from 655 to 1,434, with an 

 average for the 17 largest nests of 979. Notes are presented on intercolonial 

 hostilities^ and the area occupied by a single colony. One of the small red 

 house-ants (Solcnopsis molesta) and another species {Formica schaiifussi), 

 common in cornfields, were found inhabiting the nests of the cornfield ant. It 

 is stated that under certain conditions this ant may do considerable injury to 

 corn by direct imaided attack. Crop rotation is considered to be one of the 

 most effective means for checking the multiplication of these destructive insects. 



The wheat strawworm (Isosoma grande), F. M. Webster and G. I. Reeves 

 (U. S. Dcpt. Agr., Bur. Ent. Circ. 106, pp. 15, figs. i3).— This pest is said to sus- 

 tain about the same relation to winter wheat culture west of the Mississippi 

 River that the jointworm does to its cultivation east of this river. Both, when 

 excessively abundant, occasion losses from slight to total. In the Ohio Valley 

 and south of Pennsylvania the ranges of .these 2 insects overlap. Both species 

 are often to be found in the same field, the wheat strawworm, however, being 

 less abundant and doing usually but slight injury, while the jointworm occa- 

 sionally becomes a serious pest. 



There are two generations of the insect annually, the adults of the first gen- 

 eration differing considerably in appearance from those of the second. Indi- 

 viduals of the first generation emerge in April from the outstanding straws and 

 stubble, are very small, most of them are females, and many are wingless. The 

 females deposit their eggs in the young wheat plants, the stems of which at 

 this time extend but little above the surface of the ground. The egg is placed 

 in or just below the embryonic wheat head and the larva or woi"m works within 

 the stem, usually causing a slight enlargement. These worms develop very rap- 

 idly, and as they feed upon the most nutritious part of. the plant they become 

 more robust and larger than those found in the straw in the late summer. In 

 May the lurvaj become full grov/n and pass at once through a short pupal stage. 



In a few days the fully developed insects gnaw circular holes through the 

 walls of the stem and make their way out. 



The adults of the second generation deposit their eggs from early May in 

 Texas up to the middle of June in northern Indiana, or about the time wheat 



