224 THE CANADIAN ENTOMOLOGIST. 



Collected by Prof. C. P. Gillette, at Fort Collins, Colo., May 20, 1S98. 



The minute size of this species easily distinguishes it from any species 

 known at present. Unless considerable care is exercised only the 7- and 

 8-segmented antennte will be found, and one would, from this, be inclined 

 to call it a Dacty/opius. 



Note on a Chalcidid of the Subfam. ENCYRTiNiE, Parasitic 

 ON Phenacoccus minimus. 



BY T. D. a. COCKERELL, N. M. AGR. EXP. STA. 



Tetracnemus JVesiwoodi, r\. sp. — ^. Length i' '5 mm.; dark brown; 

 head and thorax minutely reticulated ; ocelli large and prominent, lateral 

 ocelli nearer to the eyes than to the middle ocellus ; scutellum prominent; 

 scapuliB triangular, produced to a point mesad, failing to meet by a short 

 interval only; cox?e large and swollen, trochanters small, legs long, tarsi 

 five-jointed. Antennas 8-jointed, or 10 jointed if the two ring-joints are 

 counted ; first joint of flagellum subglobose, short ; second about as long, 

 but cylindrical ; third about twice as long as second ; fourth about one- 

 third longer than third ; fifth about as long as fourth ; sixth (club) a little 

 longer. First four joints of flagellum emitting long branches as in West- 

 wood's figure of T. diversicornis. Club slender, considerably less swollen 

 than in diversicornis. Wings strongly pubescent. 



Hab. — Fort Collins, Colo ; parasitic in Fhenacoccus minimus^ Tinsley; 

 collected by Prof. Gillette. Prof. Tinsley directed my attention to this 

 interesting parasite, which he found when describing the P. minimus. 

 The parasite is almost as large as the host, and always occurs singly. 

 Prof. Tinsley observes that the head of the parasite is invariably turned 

 to the tail of the Phenacoccus. The only specimens yet available for 

 study are those mounted (after boiling) with the coccids, still enclosed in 

 the skin of the host, though fully formed in every respect. It may be that 

 specimens preserved in the usual way will show a somewhat different 

 coloration, but the structural details will not be altered. The s])ecies is 

 dedicated to the founder of the genus, who was the greatest of English 

 entomologists. It differs in the scapulae, the antennal club, and some 

 other particulars, from T. diversicornis. The genus is new to America. 

 (See L. O. Howard, Proc. U. S. Natl. Museum, XV., p. 362.) 



Since the description of Tetracnemus IVesiwoodi was written, we 

 have received many living specimens, of both sexes, from Prof. Gillette. 

 The living insect is black, with a slight metallic tinge, the mesolhorax 

 a bluish black, the scutellum purple-black, rather sharply contrasting. 

 Antennae of $ dark brown ; of ? , with scape and club, brown-black, the 

 intermediate portion white. Legs yellowish-white, tarsi more or less 

 infuscated, hind femora black. — T. D. A. C. 



Mailed August 9th, 1898. 



