78 



University of California Puhlications in Zoology [Vol.18 



(I) Binary fission 



More abundant in the crop and 

 rectum. 



(J) Multiple fission 

 (1) Somatellae 



Somatellae have not been found 

 shoAving flagellated zooids. 



(2) Internal budding 



Process comparable to that of 

 C. euryophthalmi results in a for- 

 mation of numerous small non- 

 flagellated zooids within the body 

 of the parent. 



Found in the crop and pyloric 

 expansion, but it has not yet been 

 found in the rectum. 



A few cases have shown soma- 

 tellae in the crop. These are 

 spherical in shape containing a 

 variable number of flagellated 

 zooids. 



A variable number of non-flagel- 

 lated zooids are formed within the 

 body of the flagellates in the crop. 

 The parent body degenerates set- 

 ting free the numerous small spore- 

 like forms or zooids. 



From the above tabular comparison, it will be noticed that in 

 general the differences between the two species are of two types, 

 morphological differences of minor importance, and developmental 

 differences, seemingly of great importance, especially from the stand- 

 point of transmission of the flagellate. Certain small, non-flagellated 

 forms (figs. 11, 19, 27, 35) are constantly present in the life c^^cle 

 of C. euryophthalmi. However, further investigation of the mor- 

 phology and life c^^cle of both flagellates may prove the separation 

 of these two species to be untenable. It is possible that more knowl- 

 edge of the structural modifications of these parasites due to food and 

 digestive juices of the host will account for all the differences above 

 tabulated. It must also be taken into consideration that these flagel- 

 lates are microscopic forms with few characters and that the differ- 

 ences existing between the two species of this group will be necessarily 

 slight as compared with differences betw^een two species of Metazoa. 



I am indebted to E. P. Van Duzee of the California Academy of 

 Sciences for the identification of this insect ; and to Dr. C. A. Kofoid 

 for suggestions and criticism of this work. 



Morphology of the Digestive Tract of Euryophthalmus convivus 

 The alimentar}^ tract of the bug, E uryophthalmus convivus has 

 three divisions, the fore-, mid-, and hind-gut. 



The Fore-gut. — The fore-gut as indicated in the diagram (fig. 1, 

 oes., prov.) shows the two parts, the oesophagus and proventriculus. 

 The foregut consists of the mouth, pharynx, and oesophagus (fig. 1, 

 oes.). The oesophagus is a short, delicate tube of thin, white, almost 

 transparent tissue. Following the oesophagus is the anterior end of 



