434 Scientific News. [May, 



twenty-four inches, there can be no growth of forests, and this 'is 

 the true cause of the absence of trees on the great plains. But 

 this does not prevent the existence in arid regions of certain spec- 

 ialized types of arborescent vegetation. The sage brush that 

 covers the dreary wastes of the Rocky Mountain region, the 

 Laramie plains, the Bitter creek valley, and such vast areas of 

 the West, while in its botanical characters it is little more than 

 an over-grown weed, is to all intents and purposes a tree, and 

 often attains a great age. The region it occupies is even more 

 arid than the great plains, yet no fires occur and no forests grow. 

 In the nearly rainless areas of Arizona, Southern Utah and New 

 Mexico, and stretching eastward into Texas, there occur a num- 

 ber of arborescent forms, the creosote bush ( Larrea mexicana), 

 the mesquit ( Prosopis juliflora), various acacias and mimosas, and 

 one yucca (Y.brevifolia), together with the tree cactus ( Cerens 

 giganteus). These grow scattered at great distances from each 

 other and rarely form thickets or groves. Why no such charac- 

 teristic species are found occupying the great plains- is not 

 known, and it is probably a mere accident that none happens to 

 exist, adapted both to their temperatures and their arid condition. 

 Did any such exist, there seems no reason why it might not thrive 

 as well as the sage brush farther west or the mesquit of the 

 South. 



The absence of forests or extensive tracts of timber land on 

 those areas of our Western country where the rain-fall annually 

 exceeds twenty-four inches, must, as already remarked, be attri- 

 buted to human agency in repeatedly burning over these areas, 

 whereby all forms of vegetation requiring more than one season 

 to mature their fruit are prevented from perpetuating their kind. 



— The Board of Control of the Iowa Agricultural College at 

 their last annual meeting passed a resolution that the College 

 Board would provide a competent entomologist for the State, pay- 

 ing his salary out of the college fund, provided that the legisla- 

 ture would defray the other expenses. A bill has accordingly 

 been introduced into the legislature now in session, with a good 

 prospect of becoming a law. It provides that the teacher of 

 entomology in the Iowa Agricultural College shall be tx O0fc& 

 the State Entomologist. It is made his duty to visit different 

 parts of the State upon direction of the governor, to study the 

 injurious insects. He is also to make an annual report, and this 

 report shall be in two parts, " the first of which shall be written 

 in plain non-technical English for popular perusal, while the sec- 

 ond part shall include the necessary technical descriptions." 



Provision is made for the printing and distribution of five thou- 

 sand copies of the report. Provision is also made for paying the 

 expenses of making visits to different parts of the State, and tor 

 supplying the necessary cuts and illustrations. The di 

 priation from the State treasury (not counting the printing of the 



