MEXICAN CONCHrELA IN WE8TP:RN TEXAS IN 190."^. 11 



TACm Ml) rAlt.VSITKS. 



« 



A species of the very useliil t'ninily Tachinida\ Gymnosoma fvli- 

 ginosa Dosv.. has been reaivd from achihs of the conchuehi. The 

 victims of this parasitic tlv are distinguished by the yellowish-white 

 Qgg or eaashell which remains attached to the thorax of the host 

 unless it happened to hav(> been attached to a nymph in the Hfth 

 instar, Avhich afterwards molted. On Auoiist 11 and I-! only three 

 parasitized specimens Avere discovered, two in the hfth 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 found to be more common than at the time of the 

 l^revious visit. Of 24 adults examined at that time, -1 were found 

 to be parasitized. On October i:^, of 18 adults and 81 nymphs in 

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

 "While these parasites are decidedly beneficial and may be more useful 

 under some conditions, they were not sufficiently abundant at Barstow 

 in lOO.") to explain the rapid decimation of the numbers of the con- 

 chuela which has been described under the subject of seasonal history. 



PREDACEOUS 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 pentatomids in general are characterized 

 by their ability to produce an offensive odor tliej 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 other birds,^ as Avell as the connnon toads/' seem to find 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 conchuela, the period of maximum abun- 

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

 the pest. In this it is not unlikely that birds will prove to be an 

 important if not the leading factor. 



METHODS OF CONTROL. 



Under 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 under 



a Bui. G, Div. Ovu. and Maiu.. U. S. Dept. Agric. p. r.:i. 



''Bills. 13, Biol. Surv., Dept. Agric. U. S.. pp. 2.">. CU. To; l.",, ],. 2.1; I'l. p. 4:!: 

 2X ]). 2(1. Yearbook U. S. Dopt. Agric. for ISO.j, pp. 417. 42::. t2'.i: Vi-.u-lxiok 

 r. S. I>cpt. Agric. for 11)00. ]». 414, Plates L. LI. 



'-■ Bui. 40, llute-h (Mass.) Lxp. Stu.. it. 20. Bui. \n. Ky. V.\\^. Sta.. pp. f.2. 04. 



