IIIK CATKinMLLAU: CI. .VXDS ()I'i:XIX(; EXTERNALLY. 15 



horns and is iVccd l)V tlieir cxsortion.'" ^\'llcn withdrawn, this oi'i-an lies 

 with one of its horns on cither interior side of the body, extended backwaitl 

 to tlie first ah(h)Miinal sei;Muent necordinii; to Kh-niensiewiez, hnt to tlic third 

 aeconUniL!: to Studer, who both studied the same s[)ecies, Papilio niachaon. 

 Botli -A'^vvc that a delieate uuisele is attaehcd to the tip of each horn, whieh 

 lias its insertion, aeeording" to Studer on the dorsal, but according to Kle- 

 niensiewiez on the ventral side of the l)ody. It is by this nuisclc tlmt the 

 osniateria are withdrawn, and this explains why, (hn'inii; withdrawal, one 

 may ni()\(' (piite independently of the other, and that the invagination 

 begins at the tip. The extrusion of the osmateria is presumably brought 

 about by the nuiscular contraction of the Avails of tlie body, whieh forces 

 the fluids of the body into the reversed osmateria. Inasmuch, however, as 

 all the butterflies which do not possess osmateria arc furnished, as far as I 

 have examined, on the venti-al surface of the first thoracic seginent, directly 

 in front of and between the first [)air of legs, with a more or less prominent 

 extensile bladdcr-liUe vesicle (86 :o6 ; 87 :10), which when withdrawn 

 presents a transverse slit very similar to that which is found upon the ujjpi-r 

 surface of the Papilioninae ; and inasmuch as iione of the Papilioninae 

 possess this inferior vesicle, it may be presumed that this organ may ha\e 

 a similar object ; but its precise use has never been clearly made out, though 

 it has been known since the time of Bonnet a century and a half ago. 



The abdominal glands are of two types, and, as far as is known at 

 present, are found only in the single subfamily Lycaeninae. One of these 

 tv})es (87:19) is very similar to the inferior glands of the first thoracic 

 segment, but is found a little behind the middle of the dorsal surface of the 

 seventh abdominal segment and is indicated by a transAcrse slit at this 

 point, through which there may be occasionally protruded a minute globular 

 vesicle, which seems to secrete a fluid of some sort, inasmuch as it is a point 

 of great attraction to ants. This vesicle probably exists in all the Lycae- 

 nidi as well as in some Theclidi, and though it has not been found in any 

 of our Chrvsophanidi it does occur in the European Thestor ballus. 



In addition to this form of gland there are fi)und in some species lateral 

 extensile organs or caruncles, wdiich may be seen u[)on the sides of the 

 eighth a])dominal segment (86:14; 87:14,19). These consist of exten- 

 sile organs which when fully exserted are cylindrical, with a rounded sum- 

 mit l)esprink]ed with spiculiferous needles ; excepting in Thestor ballus I 

 have been unable to find them in any group liesides the Lycaenidi and 

 here they are by no means invariably present. These curious appendages 

 were first observed by Petzhold and the attraction to ants of the central 

 o-land found upon the segment in front was first noted by Esper. ^^ hether 

 any odor accompanies the extrusion of these lateral organs of the eighth 

 abdominal segment is uncertain. In the Indian Curetis thetys (figured by 

 Ilorsfield, Cat. Lep. E. I. Co. i, pi. 12, fig. 5 — not 7 as stated in expl. pi.). 



