54 Annals Entomological Society of America [Vol. VIII, 
The short, thick glands (fig. 16, s. s. g.) in the thorax of 
Cephalothrips are usually confined to the mesothorax and 
metathorax and located laterad of the alimentary canal. These 
glands are homologous with the short, thick glands of Helio- 
thrips. In Cephalothrips these glands are longer and made 
up of smaller cells filled with vacuoles and granulated areas. 
The ducts from these glands (fig. 23) are of the same consistency 
thruout and only slightly larger than the ducts from the long 
tubular glands. The union of the salivary ducts in the head 
is somewhat different from that of Heliothrips. The ducts 
(fig. 23, 49, 52-55 and 59) of one side (1. d. and s. d.) unite and 
these united ducts meet in the center of the mouth-cone and 
form a common duct (c. d.) before entering the y-shaped piece. 
HEAD-GLANDS. 
A distinct, multinucleated and deeply staining tissue (h. g.) 
is present in definite parts of the head and mouth-cone of 
thrips and so far as known is described here for the first time 
(fig. 26, 38-48, 45, 49, 51-55, 58 and 59). This tissue, as 
far as can be determined, is of a glandular nature and it will 
be here designated as the head-gland. Its histological struc- 
ture is different from that of the thoracic glands. Num- 
erous and coarsely granulated nuclei are present; the cell walls 
cannot be differentiated; the protoplasm stains unevenly and 
no lumen could be identified. This tissue is most abundant 
in the members of the suborder Terebrantia. In Heliothrips 
(fig. 26, 38-48, 45 and 58) it occurs in three distinct regions. 
The most prominent massing occurs cephalad of the pharynx 
(h. g.) on the two sides of the dilating muscles. The extent 
and shape of these two masses varies considerably but the 
figures of the transverse sections and the lateral views of the 
pharynx show the usual distribution in this area. Distinct 
ducts (d.) arise from the dorsal ends of these masses and ex- 
tend around the lateral sides of the oesophagus and turn ven- 
trad and enter the two small openings on the caudal aspect 
of the pharynx (fig. 27, 45,46 and 58). If the above masses are 
glandular then one can readily see how their secretions may be 
poured into the pharynx and aid in digestion. Besides the 
above glandular masses cephalad of the pharynx, similar tissue 
is present at the proximal end of the left and right mandibles. 
