Dec, 1905,] Chelanops oblongus. 4^7 



two pairs, an anterior and a posterior pair. When at rest the 

 two anterior pairs extend forward and the two posterior pairs 

 backward from a right angle with the body. When walking it 

 uses its four pairs of legs quite as any four-footed animal uses 

 its legs. When disturbed it contracts its abdomen, the latter 

 thus becoming shorter and thicker. 



I focused the direct sunlight from a small engraver's lens 

 ;upon the desk, the specimen being under a watch glass. It 

 appears that in a few instances the animal took note of the 

 focus and went around it. It seems to have become conscious 

 of the focus by reaching into it with its pedipalps. At other 

 times it walked right through the focus without any concern 

 whatever. Once I directed the focus upon the cephalothorax 

 for some little time, when all at once it seemed to feel something, 

 probably the heat of the focus, and it hurried away apparently 

 discomforted. No eyes could be discovered, and the above 

 experiments, I believe, simply indicate that the animal felt 

 the heat of the focus. With a lens I could make out in many 

 instances light circular disks near the anterior lateral margins of 

 the cephalothorax. These were very suggestive of the so-called 

 €ye spots of the eyed elaters. 



Color. — The color of the adult is light brown, with the 

 pedipalps, the dorsal part of the cephalothorax and the dorsal 

 plates of a darker shade. In newly moulted specimens the 

 appendages are of a light slate color, sometimes of a green or 

 blue cast, or cream color, while the body is of a uniform yellow- 

 ish brown or cream color, with the dorsal plates not well marked 

 off. . 



Economic Value. — To what extent these little animals serve 

 any useful purpose in the destruction of insect pests, is not well 

 known and difficult to determine. But, since they are carniv- 

 orous, we may imagine that they destroy many small insects, 

 larvae and mites that would otherwise be harmful; and if Bach- 

 hausen's observations are correct, many flies, and perhaps other 

 insects larger than themselves The book scorpion no doubt 

 serves a useful purpose in keeping down the number of book-lice, 

 and to what extent this is done might be a subject for investiga- 

 tion. On the other hand a more complete study of the group 

 may show us more clearly its economic value. 



The writer desires to express his sincere appreciation to Pro- 

 fessor Osborn for his interest m.anifested in this paper and for 

 the publication of the same as a University Bulletin. 



Biological Hall, Ohio State University, November 24, 1905. 



LITERATURE. 



I. Balsan, Prof. Luigi. 1891. Vovage de M. E. Simon au 

 Venezuela, Arachnides, Chernetes. (fin) Ann. Soc. Ent. France. 

 (Did not see first seventeen pages.) 



