120 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 1 



became of real importance. The new species of Ceratnbycobius in the 

 same manner is struggling upward for recognition. The rapidity 

 with which these new parasites have adapted themselves to the boll 

 weevil, together with the facts that parasite attack begins within two 

 weeks of the invasion of new territory by the boll weevil, and that six 

 new primary parasites were added to the list during 1907, has caused 

 us to conclude that change of host relationships is not an uncommon 

 thing in at least some groups of parasitic insects. 



The peculiar distribution of the parasites and the appearance of 

 new parasites each year, prove that the boll weevil is not the original 

 host of any of them in this country. In other words, the parasites are 

 all native insects and hence are derived from native hosts. With a 

 few exceptions these native hosts are more or less closely related to the 

 boll weevil. Bracon mellitor is recorded from three species of Lepid- 

 optera and from seven species of Curculionidce. Catolaccus incertus 

 has been bred from two species of Bruchidce, and thirteen species of 

 Curculionidce. Eurytoma tylodermatis has been bred from Bruchidce 

 and Curculionidce. Ceramhycohius cyaniceps is known as a common 

 parasite of Cerambycidce, Bruchidce, and Curculionidce. MicrodoTir 

 totnerus anthonomi attacks one species each in the Bruchidce, Anthri- 

 hidce and Curculionidce. The new species of Ceramhycobius also at- 

 tacks species in these three families. 



The presence of these parasites on neighboring weevils has afforded 

 opportunity for an extensive study of weevil biologies in which over 

 125 weevil species have been more or less intimately studied. Some 

 of these weevils have ranked as injurious species in literature and 

 others of equal importance have never received economic mention. 

 The study of the biologies and parasites of these species has produced 

 several points of value, all of which will be published as rapidly as 

 time permits. 



From the standpoint of the boll weevil problem, it is of course es- 

 sential that such an important point as the diversity of host relation-, 

 ships should be utilized economicall3^ The first phase of this divers- 

 ification is an adjustable rotation of hosts, which, of course, varies in 

 consecutive years just as the variable climate affects the seasons, and 

 as other conditions affect the abundance of the host plants. The 

 parasites in the main attack weevils of few generations and conse- 

 quently must have several species of hosts in a season. When a para- 

 site matures, it evidently seeks as its host the most abimdant related 

 host species and attacks that. The boll weevil is the predominant 

 weevil species in Texas and is therefore the recipient of all parasites 

 in doubt, so to speak, about their next host. When the cotton is late, 



