44 



REPORT 108, U. S. DEPARTMENT OF AGRICULTURE. 



of which are still undescribed. Kolenati's genera Otonyssiis and Peplonyssus, para- 

 sitic on bats, appear to be larval trombidions. Many of the European larvae have lately 

 been described as new species, but it is a very undesirable practice. Oudemans hi.s^ 

 given the characters of the two groups of Trombidion larvae as follows: 



1. Two median dorsal shields Allotrombiini' . 



But one median dorsal shield Trombidivin . 



Several of our trombidions are very common, and T. sericeum Say is often seen cra^l- 

 ing about in early spring, its bright red color and silky vestiture attracting the atter 



Fig. 67.— Larva of Fig. QS.—Trombidium locustarum: 



Trombidium from Male. (Author's illustration.) 



cricket. (Original.) 



tion of even the most casual observer. In the Southwest there is a very large, hairy 

 species, T. magnificum Le Conte (fig. 70), which appears at times in enormous number>. 

 often after rains, and in parts of Arizona is called "angelitos" by the Mexicans. A 

 similar form, but spotted with white, T. superbum Banks, occurs in Texas and New 

 Mexico, and has habits similar to those of T. magnificum. T. giganteum. Riley (fig. 

 69), is a large red form feeding on grasshoppers. 



In Microtrombidium there are two claws at the end of the palpus. M. locustarum 

 Riley (fig. 68), feeds on eggs of grasshoppers. Most of the species are of good size, 



Fig. 69.— Palpus of Trombidium gignn- Fig. 70.— Palpus of Trombidium viag- 



tcum. (Author's illustration.) mficum. (Author's ilUistration.) 



some among the largest of the mites. In the Tropics there is a group of large species 

 (Dinothrombium), of which T. <mdorn/7?i Linnncus is perhaps the best known". It at- 

 tains a length of about one-half inch, and occurs in the warmer parts of Africa. It wav^ 

 supposed to be used as a dye in olden times, but does not seem to be so used now. 

 One of our species, T. marilimus Banks, lives under stones between tide marks on the 

 seashore, and sometimes feeds on a maritime coccid (Ripcrsia maritima Cockerell). 



The genus Trombclla is founded on a curious South American species, and Chyzrria 

 represents a form from New Guinea, which has projections along the sides of the bod\-. 



