Or 
(en) 
Annals Entomological Society of America (Vol. VIII, 
8. The left asymmetrical piercing organ (1. md.) is the left 
mandible and the right, rudimentary piece (r. md.) extending 
between the pharynx (ph.) and the front (fr.) is the right, 
rudimentary mandible. These mandibular parts are present 
in all thrips as far as observed. 
9. A pair of maxillae are present in all. thrips. Each 
maxilla is divided into two parts; the asymmetrical or sym- 
metrical, palpus-bearing, maxillary sclerite (mx. s.) and the 
symmetrical maxillary seta (mx.). 
10. The tentorial structures in the nymph of Heliothrips 
can be homologized with the tentorium of Cicada. On the 
basis of this homology the greatly reduced tentorium of adult 
thrips can be interpreted. 
11. The usual association between the tentorium and the 
mouth-parts in generalized insects is present in thrips and aids 
in interpreting the piercing organs. The maxillary sete are 
closely associated with the posterior arms, while the left and 
right mandibles are associated with the invaginations of the 
anterior arms of the tentorium. 
12. A comparison of the head of the nymph of Cephalo- 
thrips and the head of the adult of Heliothrips shows clearly the 
homology existing between the two suborders in respect to the 
piercing organs. 
13. The semi-pupal stage of Cephalothrips shows a distinct 
reduction in the mouth-cone. The peculiar shape of the left 
mandible and the point of attachment of the maxillary sete 
in the adult is in part due to this reduction. 
14. The pharynx at the anterior end of the alimentary 
canal is modified into a distinct and characteristic sucking 
apparatus. 
15. Two kinds of paired salivary glands are found in the 
thorax and abdomen of the two species here figured. The 
ducts from these glands unite and pass into a y-shaped structure 
caudad of the pharynx. 
16. The tissue in the head, here called head-glands, has a 
similar structure and a definite arrangement. Ducts can be 
traced from the majority of these glands to the two small open- 
ings on the caudal aspect of the pharynx. 
