84 



THE AMERICAN ENTOMOLOGIST. 



Joseph June 17, did not come from the moun- 

 tains or even from Colorado. The various states 

 of advanoemet in growth at difTeient points 

 without regard to latitude, elevation, or climate, 

 show that the broods are local, or were local 

 the present year. Their invasions of the coun- 

 try east of the Rocky Mountains, as given in 

 the December (1868) number of the Am. En- 

 tomologist, 1820, 1856, 1857, 1864, 1866, 1867, 

 and 1868 (Taylor, Smithsn. Rep. 1858 adds 

 1855), show that they are not governed by any 

 regular periodic habit or influence. Observa- 

 tion shows that ordinarily their habits on the 

 plains are very similar to those of the Red- 

 legged Grasshopper (C. femur-rubrum, Do 

 Geei'). I am inclined to the opinion that damp 

 seasons are unfavorable to their developmpnt 

 (but I will not take time at present to give my 

 reasons for this opinion). 



Do they cross the plains from the mountains 

 in one season? Or, does the same swarm travel 

 this distance? I cannot answer positively. No; 

 yet I am of the opinion that they do not. But it 

 may be asked, "Upon what do you base this 

 opinion?'" 1. The opinion of those in Colorado 

 with whom I conversed on the subject (yet it is 

 but an opinion) is that no one brood travels 

 more than thirty to fifty miles. 2. The distance 

 is so great that it raises the presumption they 

 do not, which must be rebutted by some proof, 

 which, so far as I am aware has not been fur- 

 nished — unless their appearance in Kansas from 

 the west be taken as such proof. 3. As they 

 depend upon the wind — near the mountains — 

 to carry them, it is very likely tliey depend upon 

 it on the plains. And as they are really battling 

 against the wind during the flight, their progress 

 is somewhat slow. Hence it would require a 

 long-continued series of favorable winds to 

 bear them so great a distance. (Be it remem- 

 bered I have seen them flying onlvin the moun- 

 tains, and on the plains near the base of the 

 mountains). 4. If they alight on the plains, as 

 they often do in the mountains when the wind 

 suddenly ceases blowing, coming down like a 

 pebble, their wings would be worn out by the 

 cacti and rough plants, long ere they had 

 traveled five hundred miles. 5. The swarms 

 which come from the mountains to the plains 

 near the ba! e certainly do not proceed far east- 

 ward. What reason then have we for believ- 

 ing the next brood arising from their eggs will 

 enter upon so long a journey? 



But this matter cannot be settled until more 

 facts have been obtained. 



There appear to be several varieties, varying 

 from a straw-color to a dark brassy or greenish- 



brown, the head and sides of the thorax often 

 almost black, yet retaining all the other mark- 

 ings. Age appears to deepen the color. 



Yours, etc., truly, C. Thomas. 



DeSoto, Ills. 



AN ENTOJIOLOUIST CAUGHT NAPl'lNG. 



Americans, most of them having been raise 

 in a timbered counti-y, naturally consider that 

 he normal condition of the earth is to be cov 

 ered by forests of trees. Hence we can scarcely 

 take up a scientific journal, without finding 

 some ingenious new theory to account for the 

 existence of our western prairies. These phi- 

 losophers forget that, in the interior of Austra- 

 lia, on the Pampas of South America, and in the 

 great African Sahara, you may travel for thou- 

 sands of miles without seeing a single tree; and 

 that it is no more the normal condition of the 

 earth to be covei-ed by a dense growth of woodj"^ 

 plants, than it is to be coveredby a dense growth 

 of herbaceous phenogamous plants, or a thick 

 carpet of lichens and mosses. To every soil and 

 climate a peculiar vegetation is appropriated; 

 and it is as ridiculous to saj^ that trees are the 

 natural and normal growth of the whole surface 

 of the earth, as it is to maintain that twelve is 

 the normal and natural number of a jury. 



It is amusing to see how men who live in a 

 grass country hold precisely the contrary 

 doctrine to that held by those who have 

 been reared in a timber countr)'. " Gi'ass 

 especially," says the English entomologist, 

 John Curtis, " is the natural covering of 

 THE SOIL, which has been increasing in depth 

 and bulk from the creation." {Farm Insects, 

 p. 498). If Curtis had not been better in- 

 formed in entomology than he seems to be in 

 botany, his works would not find so many read- 

 ers as they do. Entomologists and other special- 

 ists will generally find it the safest course not to 

 meddle with subjects that they do not under- 

 stand. " Let not the cobbler go beyond his last." 



THE PROGRESS OP THE POTATO BUG. 



An interesting account of the Colorado Potato 

 Bug {Dorypliora 10-Uneata, Say), is given in 

 some of the former numbers of the American 

 Entomologist. It states that, starting east- 

 ward from the Rocky Mountains in 1859, this 

 insect had already in 1868 reached the south- 

 west corner of Michigan, and Danville in Indi- 

 ana, about the centre of that State ; making its 

 average annual progress about sixty-two miles. 

 Another writer says that " the southern columns 

 of the grand army lagged far behind the north- 



