52 



opening into the cavity of ttie gland 

 and showing granular protoplasm and a 

 typical nucleus with chromatine in thc 

 shape of chromosomes. 



This is the very organ by wiiich 

 the saliva is produced. 



At the narrowest point, that is at 

 the hilus (which is in close connection 

 with the part of the supplementary 

 gland where the accessory duel ends), 

 begins the principal duct which is pa- 

 rallel to the first and enters the cepha- 

 lic cavity, opening into *he salivary 

 pump, either independently or forming 

 by anastomosis a single duct with the one 

 of the opposite side. 



The dimensions are: 



sT 



(Length: 5,30 mm. 

 ¡Width: 0,60 mm. 



íLength: 6,40 mm. 

 ^ Kvidth: 0,65 mm. 



Salivary pump. 



The impair organ of the salivary 

 apparatus, salivary pump or receptacle 

 «of the Triatoma is a conic chamber 

 with strongly chitinised walls, in- 

 side which moves a very characteristic 

 piston or embolus. 



It is found in the cephalic cavity 

 below the pharynx, on the ventral side 

 of the body. The only way to distinguish 

 its minor details is to sever the upper 

 half of the head by two lateral inci- 

 sions after keeping it for 8 to 10 days in 

 £ 4Ü0/0 solution of potash or soda. 



At the anterior end this gland forms 

 an elongated canal, coming into con- 

 tact with the mandibles; posteriorly it 

 is closed by a delicate and flexible mem- 

 brane. The emboluã Is moved by a nH 



of oblique, antagonistic, protracting andf 

 retracting muscles, the movement of 

 which causes the aspiration of saliva 

 into the interior of the chitinous recep- 

 tacle and its expulsion through the 

 salivary duct which is found in the 

 proboscis and is formed, as we have 

 seen before (1), by the application 

 of one mandible to the other. 



Physiology. 



Given the anatomy and the structure 

 of the different parts of the salivary ap- 

 paratus of the Triatoma, it is easy to 

 understand the functioning of the same. 

 The saliva is formed only in the 

 principal gland, which is the only one 

 i that shows a typic glandular texture; 

 I it passes out through the principal duct 

 ' to the salivary pump, from which it is 

 I expelled through the salivary tube 

 I found in the proboscis. 

 ¡ As for the supplementary and acces- 



I sory glands, I believe them to be simple 

 receptacles or deposits for saliva, whe- 

 re the excess of the principal gland is 

 stored. 



When the saliva in the principal 

 gland is insufficient for the demands, 

 the reserve accummulated in the other 

 two glands comes into play, running 

 out through the principal gland, thanks 

 to the communication between the prin- 

 cipal duct, at its origin, and the acces- 

 sory one. 



(l)See: Barreto, A. L, B. Notas entomológicas I- 

 Estud.os sobre a anatomia do genero Triatoma : Proboa- 

 cida e tubo digestivo. (Brasil Medico Anno 3. 1919. H. 

 cl. pag. 161.^ 



