THE VAGABOND CRAMBUS : PROBABILITIES OF ITS FUTURE. 147 



have a stout vein running into the costal margin at its middle, throw- 

 ing off a short branch inwardly ; their expanse is 0.42 of an inch. 



The insect was found dead in the box with the cocoons and puparia, 

 and it is not known, therefore, when it emerged. An example of the 

 same species in my collection bears the label, " May, 1875, from some 

 lepidopterous pupa," 



Cryptus mundus Provancher. — A third parasite upon theCrambus 

 is mentioned by Professor Riley,* as an undetermined Cryptus, It has 

 recently been determined by Mr. Cresson as C, mundus. 



Probabilities of Future Attacks. 



Questions of great interest to those who have suffered from the 

 recent depredations of this destructive insect, and to those who 

 have been studying its history, are these: Will it reappear the coming 

 season and repeat its injuries ? Will the injuries be largely increased, 

 from the immense number of eggs that have been deposited by the 

 '' clouds" of moths ? Will the species hereafter continue as a serious 

 grass-jiest ? The first two of the above queries will have been practi- 

 cally determined before these pages can reach the public ; and further- 

 more, they are virtually covered by the last. 



Our knowledge of the history of this species compels us to look upon 

 the recent demonstration as an exceptional one. It had never, so far 

 as we know, occurred before, and the records of similar attacks by 

 other species enable us to say that it will not necessarily be repeated 

 the present year and in following years. Further, we may ven- 

 ture to record our belief that they will not continue hereafter. Indeed, 

 many years may pass before we shall see it again in injurious numbers. 

 Had it been, as at first supposed, a visit from the " army-worm," we 

 could have predicted that it would not recur the following year, for the 

 immense hosts of that species are always attended by their parasitic 

 foes which so effectually destroy them that it seems impossible that two 

 *' army-worm years" can follow, in the same locality. Unfortunately, 

 the vagabond Crambus has not invited such parasitic attack. Predic- 

 tions of its future, therefore, may only rest on probabilities. 



The immense numbers of this species in its recent occurrence was 

 simply the result of a combination of circumstances which had not 

 occurred before. For reasons unknown to us, all the conditions had 

 been favorable to the development of the perfect insect. Of the eggs 

 laid by the parent moths the preceding year, nearly all produced their 

 young. The tender larva? were exempt from attack or disease during their 

 autumnal growth. During their hibernation they escaped the mortality 

 which ordinarily attends this stage; and the weather of early spring 



*Anii. Report of the Dept. of Agriculture for 1881, p. 181. 



