April, '08] JOURNAL OF ECONOMIC ENTOMOLOGY 119 



the prairie over fallen squares in wooded country. The reason is ob- 

 vious enough. The parasites choose the dryest and lightest condition 

 to be found. These very valuable observations give strong confirma- 

 tion to the value of the cultural methods, in particular the recom- 

 mendations that the cotton be planted in wide rows or checked and 

 that determinate varieties and varieties with the least amount of 

 foliage be used. 



A comparison of fields in like conditions, except for the time of 

 planting at several different places, shows that the earliest planted 

 field in each case fared the best through the early part of the sum- 

 mer at least. This is believed to be because of the rotation of hosts 

 by the parasites, and the possibihty of the hibernated parasites at- 

 tacking the boll weevil as the first or second spring host in the earliest 

 planted fields, and the necessity for one or more generations on other 

 hosts in the latest planted fields. The fact remains, however, that 

 early planting is advantageous. 



The second group, or control by the rotation of hosts, consists of 

 the encouragement of the spring host plants for co-host weevils, the 

 elimination of summer host plants in order to force over the parasites, 

 and the fall destruction of the cotton plant to insure hibernating 

 eo-hosts for the parasites. 



At present the average percentage of parasitism is very variable 

 for localities quite close together. This is directly due to the very 

 peculiar distribution of the parasites. No one species is of primary 

 or even secondary importance over the entire infested territory. Six 

 species are known to hold these positions in various portions of our 

 territory. They are, in order of greatest importance Bracon mellitor, 

 Catolaccus incertus, Eurytoma tylodermatis, Microdontomerus an- 

 thonomi, Ceramhyco'bius cyaniceps, and Ceramhycohius n. sp. Bracon 

 mellitor is predominant in Texas except in the central and eastern 

 portions. Catolaccus incertus appears as most important in south 

 Texas and Louisiana. Eurytoma tylodermatis is at its best in north 

 central Texas. Microdontomerus anthonomi is very important in cen- 

 tral Texas. Ceramhycohius cyaniceps predominates in northeast and 

 east Texas and in northwestern Louisiana. The new species of 

 Ceramhycohius is known to occur only at Victoria, Hallettsville and 

 Brownsville, Texas, and Alexandria, Louisiana. Microdontomerus is 

 a new genus of the torymid sub-family Monodontomerince, and fur- 

 nishes the first species in that family known to attack Coleoptera. This 

 species was new to science in 1906 and a very insignificant factor in 

 the control of the boll weevil. In 1907 it appeared on places care- 

 fully watched in 1906 and where it was not found before and this year 



