586 PROF. WESTWOOD ON SOME 



minis fere thoracis longitudine fulvo-testaceo ; abdomine ovali, nitido ; antennis maris corpore toto 

 dimidio longioribus, nigris, articulis duobus basalibus fulvis ; pedibus elongatis, gracilibus, fulvis, apice 

 tarsorum obscuro ; tibiis posticis in utroque sexu setosis ; alis anticis ovalibus, convexis, semiglobosis, 

 coriaceis, nigris, valde nigro-setosis ; alis posticis fere linearibus, setosis. Long. corp. 6 circ. '2 mill., 

 $ - 274 mill. ; long, anten. maris - 3 mill. 

 Habitat in graminosis in Insula Sanctas Helenas. 



Alaptus excistjs. (Plate LXXIII. fig. 10, <$ , and fig. 11, ? .) 



I am indebted to Mr. Whitmarsh, of "Wilton, near Salisbury, for an opportunity of 

 examining a very large number of glass slides, prepared for tbe microscope, containing 

 minute insects mounted in Canada balsam — an excellent plan for the examination of 

 such objects, so far as the observation of the general outline and of detached parts are 

 concerned, the gummy solution rendering the parts more or less transparent. Amongst 

 these specimens I found two insects belonging to the Mymarides, which I have no 

 hesitation in regarding as the male and female of the same species. Both specimens 

 had been reared from white blotches on oak leaves, evidently caused by the action of 

 the minute larva of one of the leaf-mining Tinece (Lithocolletes ?) . The blotches were 

 about 1^ in. in diameter. The leaves were gathered on the 9th September, 1871 ; and 

 the little Mymars appeared on the 6th October ; one of the moths appeared on the 16th 

 September, 1871, and two other kinds of parasitic flies on the 4th October following. 



The action of the Canada balsam has destroyed the colours of the insects ; so that the 

 following description is confined to structural characters ; moreover the male insect 

 has unfortunately been fixed by the Canada balsam on its side, and the exceedingly 

 minute size of the creatures rendered any attempt at displaying them, by arranging 

 the limbs in the usual manner, ineffectual. 



The head in the male is of large size and of an oval form (seen laterally), transverse 

 in the female and widest behind ; in this sex it appears to be furnished with two 

 large appendages, truncate at the tips, which may possibly be dilated palpi. The 

 antennas of the male are long and filiform, 10-jointed, the basal joint being the largest, 

 the remaining nine being nearly equal in size. The antennae of the female are 8-jointed, 

 the first joint large, the second smaller, the third considerably shorter and thinner than 

 the preceding, the fourth to the seventh gradually but slightly thickened, and the eighth 

 forming an elongated oval mass. The details of the thoracic segments are not easily 

 determined, owing to the mode of preservation of the specimens ; but the scutellum 

 seems to be of large size and semicircular. The abdomen is sessile, depressed, and 

 gradually pointed to the tip in the female, whilst it is more ovate in the other sex, with 

 the male "organ protruded. The wings are of equal size and shape in both sexes, the 

 posterior ones being as large as the anterior, which latter have a remarkable dilatation 

 near the base of the posterior margin, terminating in an acute notch ; the remainder of 

 the margins of all the wings is fringed with long hairs ; the legs are long, slender, and 

 terminated by 5-jointed tarsi with large pulvilli. 



The 5-jointed tarsi, the number of joints in the antennas of the two sexes, the sessile 

 abdomen, and the very long narrow wings, agree with the characters of Haliday's genus 

 Alaptus given by Walker in the { Annals of Natural History,' vol. xviii. (1816) p. 50. Of 



