232 REPOET OF THE COMMISSIONER OF AGRICULTURE. 



be compared with those given for the first time of devastator (Plate VIII, 

 Fig. 5). In a general way devastator may be distingaished from the 

 others by the following characters : Cerci slender, more than thrice as 

 long as broad, not narrowed at tip, but excavated at outer third ; more 

 nearly resembling those of atlanis than sp'etus; supra-anal plate ordi- 

 narily with the median ridges suddenly terminating and uniting at 

 posterior third ; tooth-like appendages at base narrow, and reaching, on 

 an average, to nearly one-half the length of the plate ; in this last char- 

 acter it more nearly resembles femur-riibrum than either spretus or 

 atlanis. The turned up anal joint is usually less swollen than in spretus, 

 and less narrow towards the tip than in atlanis, which has the notch less 

 deep and the two lobes not so well defined. 



On examining a large mass of material it will be found that there is 

 variation even in these structural details, and while it will be both cor- 

 rect and more in accordance with modern ideas of species among ento- 

 mologists to rank devastator as distinct, we are ourselves more inclined 

 to look uj)on devastator as a mere geographical race of spretus. How- 

 ever, it is immaterial whether these forms be called races or distiuct 

 species. We would refer those interested in further discussion of the 

 subject to the remarks on spretus, atlanis, and femur-ruhrum in our 

 Seventh Keport on the Insects of Missouri, pages 169-171. One con- 

 clusion that can be safely drawn from the study of large material of 

 these allied species is, that no one individual, nor a few individuals, will 

 suffice to properly distinguish the forms. It is by a total average of 

 the differences as they present themselves in large series that the spe- 

 cies are best indicated and characterized. 



Remedies. — In corresponding with those interested we recommended 

 the means that have been found most effectual against the unfledged 

 insects in the Mississippi Yalley States as set forth in the first and sec- 

 ond reports of the Commission. These include burning, ditching, and 

 the use of kerosene or coal-oil pans. A new method of warfare adopted 

 in California and set forth by Mr. Coquillett consists of the use of arse- 

 nic, sugar, bran, and water, the proportions being one part by weight 

 of arsenic, one of sugar and five of bran, to which is added a certain 

 quantity of water. The arsenic and bran are first mixed together, then 

 the sugar is dissolved in water and added to the bran and arsenic, after 

 which a sufficient quantity of water is added to thoroughly wet the mix- 

 ture. 



About a teaspoonful of this mixture is thrown uj^on the ground at 

 the base of each tree or vine, and left to do its work. The poison works 

 slowly, seldom killing its victim within less than eight or ten hours after 

 having been eaten. 



We have already expressed the belief in articles that have been pub- 

 lished that this method of destroying the locust will prove very serv- 

 iceable in orchards and gardens where the insects are not abundant, 

 but we do not think it will compare with the other methods mentioned 

 in the Commission's reports where the insects are as numerous as they 

 have been in past years in the Mississippi Valley. 



NON-MIGRATORY SPECIES. 



As but few of the reports on locust injury in the Atlantic States were 

 accompanied by specimens, it is impossible to say what particular 

 species caused the damage in each particular case, but the specimens 

 received this year from various widely different localities, in different 

 States, are all referable to three weU-known species, viz, the Eed-legged 



