SUBFAMILY ERIOCOCCINAE 123 



structures may be known as the labiae, those on the head as the 

 eephalabiae and those on the abdomen as the caudalabiae. They 

 are also known as the eye-like glands, cicatrices, fossette ostioloform 

 labiate, and dorsal ostioles. The labiae were considered by Ber- 

 lese as places where the cuticle had been invaginated for the 

 attachment of muscles. They are lip-like structures. The sides 

 or infolded surfaces of the lips or labiae bear setae and cerores. 

 The caudalabiae are generally longer than the eephalabiae, the 

 latter are sometimes greatly reduced and wanting. Between the lips 

 of the labiae there appears to be the mouth of invaginated pockets. 

 There can frequently be observed on living specimens a small 

 globule of a clear fluid over the mouth of each labia, more 

 frequently the caudalabiae than the eephalabiae, so that they are 

 probably also glandular in structure as suggested by Comstock, 

 For, as he suggested, when the specimens are stroked with a pencil 

 or dissecting needle, the insect will hump up its back and extrude 

 a globule of liquid. The insect is unable to repeat this operation 

 until the pocket is again filled with the clear fluid. Specimens 

 have been observed to extrude globules from all four labiae at the 

 same time. The labiae undoubtedly have a glandular function 

 which is probably of later origin than their earlier function, a 

 parademe for the attachment of muscles. Sulc, who has made a 

 histological study of these structures, believes that the globules 

 of sticky matter rolled in wax are for defensive purposes. When 

 they come into contact with antennae or palpi of the enemj^, as he 

 states, these appendages are all stuck up and unserviceable until 

 they have been cleaned. This fact together with the belief that 

 the excretion is derived from the fat tissue, has led Sulc to name 

 these structures the " adiopugnatorische organ." 



There is another labia on the ventral aspect of the abdomen 

 between the second and third segments, the ventralabia. This has 

 not been observed to extrude any globules. Sulc has also made a 

 careful stud}^ of this structure. He considers this labia as entirely 

 different in origin and structure from the eephalabiae and 

 caudalabiae. His published figures support his contention as to 

 their structure. He considers, I believe erroneously, this structure 

 as homologous with the stink glands of the adult heteropterous 

 Hemiptera. He also calls attention to a rudimentary structure in 

 the first abdominal segment which does not show in specimens 



