W. M. Wheeler.
A Gynandromorph of Tetramorium guineense Fabr.
Psyche 31:136-137, 1924.

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136 Psyche [June-August
A GYNANDROMORPH OF TETRAMORZUM GUINEENSE FABR.
By WILLIAM MORTON WHEELER.
Bussey Institution, Harvard University.
Mr. P. H. Timberlake has had the kindness to send me a very interesting gynandromorph of the common tropicopolitan ant, Tetramorium guineense Fabr., which was captured June 19th, 1923 by Mr. E. H. Bryan on Necker Island, some miles northwest of Honolulu. Unlike the previously recorded ant- gynandromorphs, this insect is a pure example of the antero- posterior type, the head being male, the remainder of the body female, with perfectly developed wings (Fig. la). I can detect no deviation in the structure of the head (Fig. lb) from that of the normal male. The antennae are perfectly developed and 10-jointed, and the details of the sculpture, pilosity and color of the normal male are accurately reproduced. The head of the
normal female, shown in Fig. lc, is, of course very different. The thorax, however, is precisely like that of the normal female, except that it is slightly less robust, with the mesonoturn a little less flattened dorsally, and the metasternal spines are un developed. The thorax of the male guineense is very different from that of the female, since it lacks the epinotal spines as well as the metasternal spines, has a more convex mesonotum and mesosternum and the former has Mayrian furrows. The color is also darker and the surface much smoother and very differently sculptured from that of the female. The legs, petiole, post- petiole and gaster of the gynandromorph are precisely as in the normal female, even the sting, which is fully exserted, being of the same length and structure. The sculpture, pilosity and color are also as in the normal female, the thorax, legs and pedicel being yellowish ferruginous, the gaster very dark brown or blackish, with its extreme base and tip yellowish brown. There is every reason to assume that the internal reproductive organs are those of the normal female. The wings are whitish hyaline, with colorless veins and pterostigma, as in the normal female. On looking over the specimens of Tetramorium guineense in my collection I find one male from Cagues, Porto Rico with



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19241 A Gynandromorph of Tetrarnorium guineense Fabr. 137 an 11-jointed left antenna. The right antenna is broken so that the number of its joints cannot be ascertained. This and similar specimens, which one finds occasionally in Tetramorium and other ant-genera, are probably to be regarded as exhibiting "intersexual" rather than gynandromorphic traits since in the case mentioned the number of antenna1 joints is intermediate between the ten of the normal male and the twelve of the normal female.
Fig. 1.
Gynandromorph of Tetramwium guineense. Fabr. a, lateral view; b, anterior
view of head; c, head of normal female.




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