Burgess.] 294 [January 23, 



short muscles filling the large vaulted clypeus (figs. 2 and 9, c. m.), 

 are attached to the ends of these strings, and by their contraction 

 close the oesophagus. Just below the " front " a fine duct (I. d.') 

 opens, which is the common duct of a pair of lingual glands, pres- 

 ently to be described. Just below this bone there is a double ele- 

 vated ridge covered with short hairs (fig. 10). 



The lower lip (fig. 3) is composed of an oblong mentum (m.), bear- 

 ing a larger labium (lb.) narrowed at the base, then expanding so 

 as to have a bi-sinuate, almost S-shaped lateral outline; the lower 

 edge bears two short, broad lobes, and two stumpy, one-jointed 

 palpi (/. p.). 1 The labium in profile (figs. 1 and 2) is very thick, and 

 the lower edge is divided into two narrow laminse, while still a third 

 lamina, well separated from the first two, forms the "tongue" (figs. 

 1-4, t.). Within the tongue lies a pair of peculiar organs which 

 may be called the " lingual glands " (figs. 2 and 3, I. gS). These can 

 be seen through the semitransparent mentum and labium, as in fig. 3, 

 offering an irregular obovate outline. A short duct from the lower 

 end of each gland leads into a common duct (I. d.), which opens in 

 the oesophageal bone, as already described. 



The ducts curve over the lower end of the glands and run up their 

 posterior surface, to which they are soldered, nearly to the top. The 

 line of the ducts, together with the lateral outlines, give the glands a 

 three-cornered shape, somewhat, like that of a butternut. A little 

 triangular cap fits on the summit of each gland, and on it is inserted 

 a suspensory muscle, the upper end of which is attached to the cra- 

 nium (g. m., figs. 2 and 3). The specimens at my command have 

 not been fresh enough to study the histology of these organs, but 

 they seem to be composed of an outer sack, with a thin, tough wall, 

 which is light yellow, and has a slightly roughened or granular sur- 

 face. The interior is filled with cells, and perhaps may be glandular. 

 The excretory ducts are thick-walled and strengthened by circular 

 threads, as is often the case with the salivary ducts of insects. 2 



These organs, as will be seen from this description, are very unlike 

 the salivary glands of other insects, and are, whatever may be their 



1 "With "Westwood I regard these pieces as true palpi, and not as a second pair 

 of labial lobes. 



2 The salivary ducts in most insects open by distinct apertures into the oesopha- 

 gus, still they unite into a common duct in many Diptera and some Orthoptera. 

 See Siebold, Anat. Invert. Siebold excepts only Mantis among the Orthoptera, 

 but Blatta, Termes and the Acrydians, at least, must be added. The occurrence of 

 salivary glands confined within the head is also unusual, but not •without precedent. 



