ZOOLOGY. 453 



is concealed from view by a movable piece or hood attached 

 to the tenth urite, and which he calls the velum penis. He 

 also distinguishes the uro-patagia (lateral inferior flaps de- 

 veloped from the supra-anal plate), and has studied the dis- 

 tribution of the sympathetic nerve and the terminal abdom- 

 inal nerves, which are distributed to the female internal and 

 external reproductive organs. 



The sixth report of the State Entomologist of Illinois, Pro- 

 fessor Cyrus Thomas, appears with much matter that will be 

 useful to farmers and gardeners. 



The transformations of the locust mite, the little red mite 

 so annoying and sometimes destructive to the Rocky Moun- 

 tain locust, have been discovered by Professor Riley, and 

 published in the report of the United States Entomological 

 Commission. 



Further researches by Mr. Riley on the gall-producing 

 plant-lice, allied to Phylloxera, the grape-vine pest, are of in- 

 terest. Recently Dr. Kessler, of Cassel, by a series of ingen- 

 ious experiments, has concluded that these insects hibernate 

 on the trunk of the elm. In 1872, Mr. Riley, led by his pre- 

 vious investigations into the habits of the grape Phylloxera, 

 discovered that some of our elm-feeding species of Pemphigi- 

 nce produce wingless and mouthless males and females, and 

 that the female lays but one solitary impregnated egg. Con- 

 tinuing his researches the past summer, he has been able to 

 trace the life history of those species producing galls on our 

 own elms, and to show that they all agree in this respect, and 

 that the impregnated egg produced by the female is con- 

 signed to the sheltered portions of the trunk of the tree, and 

 there hibernates, the issue therefrom being the stem-mother 

 which founds the gall-producing colony the ensuing spring. 

 "Thus the analogy in the life history of the Pemphigince and 

 the Phylloxermw is established, and the question as to what 

 becomes of the winged insects after they leave the galls is no 

 longer an open one. They instinctively seek the bark of the 

 tree, and there give birth to the sexual individuals, either 

 directly or (in one species) through intervening genera- 

 tions." 



A swarm of locusts (Acridium peregrinwri) is reported in 

 Psyche to have boarded the ship Harrisburg, of Boston, on 

 the passage from Bordeaux, bound to New Orleans, on the 



