p 



ANTS. 



from one ant to another. The ants try to rid themselves of the para- 

 sites when these first attach themselves, but after they have taken up 

 their definitive, symmetrical positions, they seem to be tolerated with 

 indifference. There is nothing to indicate that the ants, while cleaning 

 one another, are even aware of the existence of the parasites. The 

 relations of the allied American ectoparasitic mites to their host ants 

 have not yet been studied. Echinomegistus wheclcri ( Fig. 245, A and 

 B), which occurs on Lasins aphidicola, is probably very similar to 

 .-I ntcnno Chorus in its habits. 1 



The number of mites living in the nests or on the surfaces of ants 

 seems to be very great. Berlese, in a recent work (1904) has described 

 more than sixty species of myrmecophilous Gamasidse alone. The 

 habits of a few of these have been studied by Janet and Wasmann and 

 may be very briefly described. Cillibano [Discopoina] cornata is a 

 peculiar tortoise-shaped mite which attaches itself to the workers of 

 Lasiits nii.vtits and its larvae (Fig. 246). On the ants it always assumes 

 a definite position. According to Janet, when only one is present, it 

 places itself on the side of the second gastric segment. If there are 

 two, they place themselves symmetrically, one on each side. If there is 



a third, it is attached in the 

 mid-dorsal line of the same 

 segment. Rarely as many 

 as six may be present; in 

 which case there are three 

 also on the third gastric 

 segment in positions cor- 

 responding to those on the 

 second. The ants dislike 

 the Cillibano and tear them 

 to pieces whenever they 

 can seize them. The mites, 

 however, usually slip out 

 of their mandibles or apply 

 the edges of their bodies so closely to the surfaces of the ants that they 

 cannot be picked off. From scars (Fig. 246, B, C, w) left on the inter- 

 segmental membranes of the ant's gaster Janet infers that the Cillibano 

 sucks the blood of its host. The types of another Cillibano ( C. hirti- 

 coina), with long, flexuous dorsal hairs, were found by me in Texas on 

 an Kciton scliniitti queen (Figs. 147, c; 245, C,D). This mite attaches 

 itself not only to the body, but also to the antennae and legs of its host. 



'I have recently found an undescribed species of Antennophorus on our 

 North American Acanthomyops inlcrjcctus. 



FIG. 252. A, Normal pupa of Pheidole in- 

 stabilis worker ; B, and C, phthisergates, pro- 

 duced by parasitism of Orasema viridis larvae on 

 the larvae of the same ant. (Original.) 



