SUMMARY. 213 



arrived. Eeports have reached us of the attempted colonization of this 

 bird in parts of the cotton-growing regions of Texas. The persons who 

 carried this plan out did not learn from experience of the bad habits of 

 the sparrow for the simple reason that he would not stay. In a very 

 short time after their importation in considerable numbers hardly a spar- 

 row was to be found in the State. Persons interested in the experiment 

 believed that the climate was too warm, and suggested as the only means 

 of bird relief the importation of some South American sparrow of sim- 

 ilar habits. We very much doubt, however, if any bird could be intro- 

 duced which would prove a greater blessing than any one of many birds 

 indigenous to the cotton States, if equally encouraged. 



With the exception of the ants, predaceous insects are hardly to be 

 compared either to the birds or to the parasitic insects in regard to the 

 number of cotton worms which they destroy. True, the capacity of some 

 of them is great, but they either labor under disadvantages (such as being 

 comparatively confined to the ground, as the carabid beetles) or are not 

 sufficiently numerous to do a very great amount of good. Still it is well 

 to know them and not destroy them, as thousands of worms are destroyed 

 by them, and it is only in a comparative way that we speak at all dep- 

 recatingly of them. The capacity of the rear-horses (Mantis Carolina) 

 has been shown by the statement that one individual has in one night 

 killed and devoured eleven Colorado potato-beetles, and we have men- 

 tioned the fact that a young specimen of the wheel-bug (Prionotus cris- 

 tatus [Reduvius novenarius] ) has been known to destroy ten caterpillars 

 in five hours, thus showing the amount of good which may be done by the 

 hemipterous enemies of the cotton- worm. The destructive powers of the 

 asilus-fl ies have been shown from Mr. Thompson's statement that he has 

 known one individual to destroy 141 bees in a day. The work of ants 

 in this direction has been discussed at length, and they are shown to be 

 the most valuable of the predaceous insect enemies of the cotton- w^orm. 



The destruction of the cotton- worms by their true parasites is a sub- 

 ject upon which interesting experiments may be made. The extent of 

 parasitism will undoubtedly vary much with the season of the year, the 

 last brood always seeming to be much more extensively parasitized than 

 any of the preceding broods. The probabilities are that they increase 

 with the increasing numbers of the worms, and that they also are affected 

 to a certain extent by the character of the season, although not com- 

 parably with the ants. From August 12 to August 28, 1721 pupae, 

 probably belonging to the fourth brood, were received at the depart- 

 ment from Mr. Trelease at Miuters, Dallas County, Alabama, for the pur- 

 pose of ascertaining the extent of the parasitism. The result hardly 

 justified the anticipation. From this lot of 1,721 chrysalides there is- 

 sued in all 1,455 moths, and from the remaining 266 chrysalides were 

 bred the following parasites: Of Chalcis ovata, Say, 32 specimens; of 

 Tachina aletiae, Kiley, 3 specimens ; Of Sarcophaga sp., 7 specimens ; 

 of Pimpla anulipeSj Br., 1 specimen ; of Tachina sp ., 2 specimens ; of 



