80 BRITISH BUTTERFLIES. 



testes form two lobes of a not very distinctly reniforin shape, whilst the 

 ovaries, which are only to be seen with a lens, and then in comparatively 

 few species, are much smaller and consist of tubes. The testes are 

 generally much more readily observed than the ovaries, being usually 

 yellow or brown, and may be seen distinctly in the larvae of those 

 species of lepidoptera that feed internally, or that have fairly transparent 

 skins. Jackson says that the larval ovaries are situated in the 5th 

 abdominal segment and close to the dorsal middle line. Their proximal 

 or attached extremities are approximated, and they diverge from one 

 another posteriorly. The colour gets deeper during the quiescent 

 period preceding pupation. Four opaque white lines, the future 

 ovarioles, traverse the larval ovaries lengthwise, and converge towards 

 their hinder extremities, from which the larval oviducts spring. The 

 latter are very delicate filaments, and difficult to make out. Bessels 

 notes of Pieris brassicae that the ovary is yellow, the testes violet, the 

 fat -body white. 



CHAPTER IX. 



THE ASSOCIATION OF ANTS WITH BUTTERFLY LARVAE. 



A matter, of which little is known, has here to be considered, viz., 

 the character of the association of ants and certain Ruralid larvae. On 

 the middle of the dorsum of the 7th abdominal segment in these larvae 

 is an evaginable gland, which, in some species, secretes tiny drops of 

 sweet fluid, greedily lapped up by ants, that stroke the larvae with 

 their antennae until the desired liquid is obtained. Other allied larvae 

 are said to possess the gland, without, however, its having any 

 secretive powers, and it is recorded that these larvae are not 

 accompanied by ants. Until, however, many more observa- 

 tions have been made, this latter conclusion must be accepted 

 with great caution. It is assumed that, whilst the ants benefit by 

 obtaining the saccharine fluid desired, their presence tends to warn off 

 ichneumons and other enemies that prey on the larvae. Scudder 

 observes that " it is a curious thing that, among the Lycaenidi, the 

 glands are found in some species, whilst not in others closely allied; 

 their presence in many members of the other two tribes of Lycaenidae, 

 together with the impossibility of their independent origin in different 

 genera, render it probable that these glands first arose as long ago as 

 before the differentiation of the three Lycaenid tribes ; the brotherhood of 

 the ants and caterpillars may, therefore, be of great antiquity." Scudder 

 says that Esper was the first to notice the relation of the larva and the 

 attendant ants, and that Guenee observed the gland in the larva of 

 Lampides boeticus, describing and figuring it, whilst Freyer figures 

 the gland as two white dots in the larva of Plebezus argus, but does not 

 describe it. Scudder observes that the gland is present in the Larvae of many 

 hair-streaks, and in that of Thestor b alius, although the association of 

 ants with these larvae has escaped notice. 



Edwards gives [Can. Ent., x., pp. 131-186) a detailed account 

 of the connection between the larvae of Cyaniris pseudargiolus and 

 their attendant ants, He noted that ants frequented the same 



