MEXICAN CONCHr^ELA IN WE.'^TERN TEXAS IN l!»o:,. H 



TACIIIXID TAltASITES. 



A species of the very useful family Tacliiiiida', Gijriinosoma fiili- 

 ginosa Desv.. has been reared from adults of the couchuela. The 

 victims of this parasitic fly ai-e distinguished by the yellowish- white 

 (.o-<r or egashell which remains attached to the thorax of the host 

 unless it hapi)ened to have been attached to a nymph in the fifth 

 iustar. which afterwards molted. On August 11 and \-l only three 

 j)arasitized specimens were discovered, two in tlie lifth nymphal 

 instar and one an adult. An adult of this species of Tachinida> was 

 bred from one of these bugs. On September 12 parasitism by these 

 tachinids was fonnd to be more common than at the time of the 

 j)revious visit. Of 2+ adults examined at that time, -4 were found 

 to be parasitized. On October 13, of 18 adults and 31 nymphs in 

 the fifth nymphal instar, 2 only had been parasitized, both nymphs. 

 ^Vhile these parasites are decidedly beneficial and may be more nseful 

 under some conditions, they were not sufficiently abundant at Barstow 

 in 1005 to explain the rapid decimation of the nmnbers of the con- 

 eliuela which has been described uiuler the subject of seasonal history. 



I'KKDACEOl'S ENEMIES. 



Although no observations on the subject of predaceous enemies 

 were made at Barstow. it seems important to refer briefly to the 

 records of observations by others along this line, in order that it be 

 not inferred that because ])entatoniids in general are characterized 

 by their ability to produce an offensive odor they are immune to the 

 attacks of insectivorous birds and of toads. On the contrary the 

 crow" is believed to be especially fond of bugs of this group, and 

 many otliei- l)irds.'' as well as the comnu)n toads.'' seem to Hnd them 

 unobjectionable as food. If we accept the evidence of definite reports 

 and observations during three successive seasons as indicative of the 

 usual seasonal history of the couchuela. the })eriod of maxinnim abun- 

 dance is followed closely by a marked nnluction in the numbers of 

 the })est. In this it is not unlikely that birds will prove to be an 

 important if not the leading factoi-. 



METHODS OF CONTROL. 



TTnder some conditions farm practices, such as the destruction of 

 weeds in the fall and otherwise hindering the sucessful hibernation of 

 the conchuelas. would be of unquestioned value in control, but niuler 



o Bui. 0, Div. Orii. and Mam.. U. S. Dept. Agric, p. 63. 



6 Bills. 1.3, Biol. Surv.. Dept. Agrle.. U. S., pp. 2.5, G2, 70 ; 15. p. 23 ; 21. p. 43 ; 

 23. p. 26. Yearbook I'. S. Dept. Agric. for 180.5. pp. 417. 423, 42i) : Yeavboolc 

 U. S. Dept. Agric. for lUOU. p. 414, Plates L. LI. 



<-Bul. 46, Hatch (Mass.) E.\p. Sta., p, 26. Bui. "Jl. Ky. Exp. Sta.. pp. 62. fU. 



