80 



PRACTICAL PARASITOLOGY 



side by side in the same intestine, they are readily distinguishable 

 from one another. 



(1) Gregarina polymorpha (Hammerschm.), Stein. Cylindrical; 

 without constriction at the junction of proto- and deutomerite ; round 

 nucleus ; oval cysts ; size, up to O35 mm. in length and O'l mm. in 

 breadth. 



(2) G. cuneator, Stein. Of about the same size as G. polymorpha; 

 constricted at the junction of the proto- and deutomerite ; the proto- 

 merite is thickened at its rounded anterior end and thinned into a 

 kind of neck where it joins the deutomerite, while the latter is 

 thickened at its posterior end into a blunt cone ; nucleus round ; 

 cysts oval. 



(3) G. steini, Berndt. Much rarer than the first two varieties ; 



in size, only up to 0'15 mm. 

 in length, and 0'04 mm. in 

 breadth ; spindle-shaped, taper- 

 ing into a long cone at the 

 hinder end ; nucleus oval ; cysts 

 oval. 



(4) Steinina ovalis (Stein), 

 Leg. and Dub. The smallest of 

 the four varieties, and for this 

 reason the one most frequently 

 overlooked ; it never exceeds 

 about O'l mm. in length and 

 0'045 mm. in breadth; the 

 deutomerite is broad and egg- 

 shaped ; the protomerite is 

 short and cylindrical, ending in 

 a more or less sharp point; 

 nucleus round and compara- 

 about O'l mm. in diameter and 



FIG. 23. Gregarines from the gut of the 

 mealworm. (After Berndt.) a, Gregarina 

 cuneata. &, Gregarina polymorpha. c, Gre- 

 garina steini. d, Steinina ovalis. Magnified, 

 a and 6, 100 : 1 ; c and d, 330 : 1. 



tively large ; cysts round or oval, 

 without sporoducts. 



All four of these varieties are very fairly frequent, and one of them 

 is certain to be found after examining two or three mealworms. 



The intestine of the mealworm is prepared and teazed out in the 

 same way as the intestine of the centipede. The fat-body of the meal- 

 worm is, however, very much more developed than that of the centi- 

 pede and care must be exercised to remove every particle of fat before 

 teazing out the intestine, or the specimen will be cloudy. The 

 Gregarines, which are usually present in large numbers, are easily 

 seen with a low-power lens. Their movements rarely take the form 

 of contractions ; they are, rather, a species of gliding movement, which 

 is performed, however, without any perceptible change of form. 



