NATURAL CONTROL. 73 



about the floor. The cockroach was caj)tured and sent to the Bureau 

 of Entomolog}^ where it was identified by Mr. A. N. Caudell as a 

 nymph of Thyrsocera cincta Burm., a species occurring in the south- 

 ern United States, Mexico, and Central America. A similar habit by 

 individuals of this species was subsequently observed by the senior 

 author on one or two occasions, but the number of ants destroyed 

 by this insect is certainly inappreciable. 



A jumping spider of the family Attidre was seen to capture a few 

 workers, and various species of the cobweb weavers (Theridiidse) had 

 the habit of reposing beneatli the stands supporting our artificial 

 formicaries and there depleting the colonies under observation. In 

 fact, so persistent were they that it was necessary to examine the 

 stands daily and destroy these spiders. Among the most abundant of 

 these was one which was identified by the late Prof. B. H. Guilbeau, of 

 the Louisiana State University, as Theridium tepidanorum. Spiders 

 of this family were not observed destroying ants in outdoor colonies, 

 but it is possible that they do so. 



On one occasion Mr. G. A. Runner observed an English sparrow 

 industriously picking up the Argentine workers from a trail which 

 crossed a wide roadway at Baton Rouge. This habit is not, how- 

 ever, a common one with this bu'd. 



The flicker or yellowhammer, Colaptes auratus, has often been seen 

 industriously digging up shallow ant nests in lawns and grass plats, 

 evidently for the purpose of obtaming the pupa* and larvae, and 

 should doubtless be credited with being the most important natural 

 enemy which this ant has in the South. Our knowledge of the extent 

 to which native birds subsist upon tliese ants is very limited as yet, 

 and the subject is one well worth more complete investigation than 

 we have been able to give it. 



EXPERIMENTS WITH PEDICULOIDES. 



The idea of finding some j)arasite which would destroy the ants 

 naturally suggested itself early in our investigations. Owing to the 

 readmess with which the small parasitic mite, Pediculoides ventricosus 

 Newp., parasitizes the larvae of wasps and beetles whenever it. can 

 obtain access to them it was thought worth while to see if this para- 

 site could be successfully used against the ant. For our experiments 

 we first reared enormous colonies of these mites on living wasp larvae 

 and thereafter placed these infested larvae in the formicaries, where 

 they could be closely observed. The following experiment will illus- 

 trate the results obtained : 



For the experiment we selected a large populous ant colony which 

 was domiciled in a plaster of Paris Janet cage of several chambers. 



