ON SOME ABNORMALITIES IN ANTS. 83 



antenna ; as Mr. Stelfox has shown me a number of other F. fuaca 3 ^ 

 (taken in Ireland by Mr. Phillips) with toothed mandibles, which are 

 in every other respect normal and perfect. 



No. 6. (Fig. 6.) Leptothora.i: arerforniii, F., deiil. ? . Taken in a 

 mixed nest of L. acen-unnii and Ji. riKjinodis, at Mauley Bog, Keighley, 

 by Mr. Butterfield, on April 26th, 1918, who kindly presented the 

 specimen to me. It is a small deiilated female, rather dark in colour, 

 and is exceed i)i(/li/ remarkable in that it poi?sesses no trace of either a 

 petiole or a post-petiole ! The gaster is joined directly on to the 

 epinotum by the small neck which joins the post petiole to the gaster 

 in normal 9 ? . It measures 3-3mm. in length. The gaster shows 

 the usual foar segments (though this is not apparent in the figure) to 

 be seen in ants which possess a two-jointed pedicel. The peculiar con- 

 struction of this specimen would appear to represent a reversion to an 

 ancestral form. One of the chief characters by which ants can be dis- 

 tinguished from all the other members of the order Hymenoptera is the 

 construction of the abdomen, which is divided into two very distinct 

 regions, a slender very movable pedicel of one or two joints, and a 

 larger posterior portion, the gaster; though in certain low forms in the 

 Ponerinae the construction of the abdomen comes nearer to that of 

 some of the Fossores. 



No. 7. (Fig. 7.) AcaiithniinjopH [DoniatJinrpea) ni(iei\ L., del. $ . 

 Bloxwortb, Dorset, from the collection of the late Rev. 0. Pickard- 

 Cambridge, and kindly given to me by his son, Mr. A. W. Pickard- 

 Cambridge. 



The scale is very emarginate, otherwise the insect is quite normal. 

 This is a simple case of variation ; the scale in the female of A. (/>.) 

 nitjer usually being somewhat emarginate, but not to the extent shown 

 in this specimen. In the genus Formica the scales in the females and 

 workers of F. mfa, L., /''. prateiisis, Hetz., 3bnd F. e.rsecta, Nyl., are 

 known to vary in this way. The scales in the workers of F. mfa are 

 usually not emarginate, though I have found colonies in which all the 

 ants possess emarginate scales. In F. crxecta the scales are usually 

 considerably emarginate, though less so in some cases. 



This paper is No. Ill of a series of notes and papers, etc., on 

 Myrmecology which I have published up to date. As the last list 

 published [Ihiti^h Jnts, liiblioijiajiliij, p. 357 (1915)J only gives such 

 papers up to No. 74, it has been suggested to me that I should publish 

 a list of the rest : — 



No. 75. " Genital Armature of the Male Ant," I'mc. I'.nt. Soc. 

 Loud., 1915, l.-liii. (with a Historical Chart). 



No. 76. "Marriage-flights of VotiistliDrpea species on August 8th, 

 etc.," Eiit. Uecnid, 27, 206-207 (1915). 



No. 77. "British Ants, their Life Flistory and Classification," 

 Brendon and Son, Plymouth (1915). (pp. xv. -f 379, with 18 plates 

 and 92 text figures). 



No. 78. "The T\pe of Canipouotiix [Mi/niioti(rha) maciilatiis, I'.," 

 /•:iit. Record, 27, 221-22 (1915). 



No. 79. "Descriptions of a Pterergate and two Gynandromorpbs 

 of M>/n)iica scabrinodis, Nyl., with a list of all the known cases of the 

 latter," F.nt. Record, 27, 25H-GO (1915). 



