1908] Catalogue of the Genus Alaptus 185 



5. Alaptus excisus Westwood. 



Westwood, 1879, p. r-,S(i. 



Riley and Howard, 1893, p. 2G7. 



Dalla Torre, 1898, p. 428. 



"I am indebted to Mr. Whitmarch, of Wilton, near Salisbury, for an oppor- 

 tunity of exaniininij a very large number of glass slides, prepared for the micro- 

 scope, containing minute insects inounted in Canada balsam — an excellent plan 

 for the examination of such objects, so far as the observation of the general out- 

 line 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 Tineae (i.ithocolletes?). The blotches were about 1 >4 in. 

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

 little Mvmars appeared on the 6th of October; one of the moths appeared on 

 the 16th of September, 1871, and two other kinds of parasitic flies on the 4th 

 of October following. 



The action of the Canada balsam has destroj^ed the colors of the insects; 

 so that the following description is confined to strtictural characters; moreover 

 the male insect has unfortionately been fixed by the Canada balsam on its side, 

 and the exceedingly minute size of the creatures rendered any attempt at dis- 

 playing them, by arranging the limbs in the usual inanner, ineffectual. 



Ihe 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 antennae 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; bttt 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 se.x, 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 antennae 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 (1846) p. 50. Of this genus two or, more probably, only one species 

 is recorded in this coimtry, namely A. minimus, "ferruginosus, an tennis et 

 pedibus pallidis"; the supposed second species, .4. fiiscidas, "Praecedente 

 major colore obscurior antennis longioribus, vix revera species distincta". 

 (op. cit. p. 51). Another species, A. paUidornis (?pallidicornis), is slightly des- 

 cribed by Foerster, found near Aix la Chapelle. It is scarcely half as long as 

 A. minimus, with 5'ellowish-white antennae (Hym. Stud. II, p. 120). As these 

 authors do not mention the singular dilated and excised base of the forewings,t 

 I consider the one before us distinct, to which may be applied the name of 

 Alaptus exctsus. 



A. antennis maris corpore paullo longioribus, feminae corpori aequalibus; 

 aHs anticis basi postice dilatatis et subito excisis. Insecta minutissima. Long, 

 circ. 1-6 mill. 



* This dilatation is present at least in the females of iceryae Riley, and both 

 sexes of caecilii Girault and eriococci Girault, and those of minimus Walker, 

 so that the character is generic and not specific; to a less extent, it occurs in 

 other genera. It is particularly strong in minimus. 



f Compare the previous footnote in regard to this. 



