THYSANURA. i277 



tera; for Mr. P. Smith informs me that throughout nearly the 

 whole of this large group, the males, in accordance with the gen- 

 eral rule, are smaller than the females, and emerge about a week 

 before them; but amongst the Bees, the males of Apis mellifica, 

 Anthidium manicatum, and Anthophora acervorum, and amongst 

 the Fossores, the males of the Methoca ichneumonldes, are larger 

 than the females. The explanation of this anomaly is that a 

 marriage flight is absolutely necessary with these species, and the 

 male requires great strength and size in order to carry the female 

 through the air. Increased size has here been acquired in oppo- 

 sition to the usual relation between size and the period of de- 

 velopment, for the males, though larger, emerge before the 

 smaller females. 



We will now review the several Orders, selecting such facts as 

 more particularly concern us. The Lepidoptera (Butterflies and 

 Moths) will be retained for a separate chapter. 



Order, Thysanura. — The members of this lowly organized order 

 are wingless, dull-colored, minute insects, with ugly, almost 

 misshapen heads and bodies. Their sexes do not differ; but they 

 are interesting as showing us that the males pay sedulous court 

 to the females even low down in the animal scale. Sir J. Lub- 

 bock" says: "it is very amusing to see these little creatures 

 "(Smynthurus luteus) coquetting together. The male, which is 

 "much smaller than the female, runs round her, and they butt 

 "one another, standing face to face, and moving backward and 

 "forward like two playful lambs. Then the female pretends to 

 "run away and the male runs after her with a queer appearance 

 "of anger, gets in front and stands facing her again; then she 

 "turns coyly round, but he, quicker and more active, scuttles 

 "round too, and seems to whip her with his antennse; then for a 

 "bit they stand face to face, play with their antennae, and seem 

 "to be all in all to one another." 



Order, Diptera (Flies). — The sexes differ little in color. The 

 greatest difference, known to Mr. F. Walker, is in the genus 

 Bibio, in which the males are blackish or quite black, and the 

 females obscure brownish-orange. The genus Elaphomyia, dis- 

 covered by Mr. Wallace^* in New Guinea, is highly remarkable, 

 as the males are furnished with horns, of which the females are 

 quite destitute. The horns spring from beneath the eyes, and 

 curiously resemble those of a stag, being either branched or pal- 

 mated. In one of the species, they equal the whole body in 

 length. They might be thought to be adapted for fighting, but 

 as in one species they are of a beautiful pink color, edged with 



" 'Transact. Linnean Soc* vol. xxvi. 1868, p. 296. 

 '8 'The Malay Archipelago," vol. ii. 1869, p. 313. 

 19 



