PARTULA HYALINA. 43 
the species was lacking in a collection comprising 409 adult specimens. In 11 valleys 
it was impossible to find a single example of hyalina, either full-grown or immature. 
It is certain, then, that this species is absolutely more abundant in some valleys 
than it is in others, even though it appears that a higher proportion is indicated for 
the valleys from which the largest collections were obtained, like Fautaua. It is 
only a coincidence that hyalina should happen to be more numerous in certain 
valleys to which several excursions were made on account of special interest in other 
species. 
Tasie 10.—Percentage of hyalina in relation to size and location of valleys. Tahiti. Full data. 
Number of valleys inhabited by hyalina 
Index of to the extent of— Average 
Region. size of valley 
valleys. 0 Otol 1 to2 2to5 |5 percenticollection. 
per cent.| per cent.| per cent.jand over. 
I ai: on ae a 2 815 
Northern quadrant..... II $0 ee 1 3 ae 725 
Ill iw: 2 1 1 as 383 
I 50 1 is 40 is 756 
II a 1 AS 1 ag 408 
Western quadrant...... Ill 3 HF 2 ae i 457 
IV ae ae 1 1 ea 697 
li 1 3 UW: b 6 ws 450 
Southern quadrant...... ae : : 1 : i ue) 
IV 3 2 2 1 1 238 
II 50 AY, 1 2 AG 383 
Eastern quadrant....... Il i: 3 1 ra iS 429 
IV 2 Ae aS 1 ite 262 
hahition lineerereeereeckiarerct 11 15 10 11 3 437 
Tasie 11.—Percentage of hyalina in relation to size and location of valleys. Tahiti. Summaries. 
Number of valleys inhabited 
NoveE by Ayalina to the extent of—| Average 
valleys. valley 
0 0to2 /|2 per cent|collection. 
per cent.| and over. 
Index of size of valleys: 
FO OTTO CO OG OUOOROO.S 7 1 4 2 599 
1D ici inteinihorcncet ic 16 2 7 7 489 
NaS ooaonosoeUSUaod © 13 3 9 1 425 
IS oe Mee ctr btae ace 6 14 5 5 4 309 
Region: 
Northern quadrant..... 10 et 4 6 606 
Western quadrant...... 10 3 2 525 
Southern quadrant..... 20 6 11 3 345 
Eastern quadrant....... 10 2 5 3 365 
shahitimnultesey err 
On the basis of the foregoing facts, we are led to ask whether the abundance or 
scarcity of hyalina might be related to or dependent upon distinctive ecological 
characteristics of the major quadrants of Tahiti nui and of different valleys located 
in these quadrants. To answer this question we may tabulate the percentage 
frequencies of this species in correlation with the size-indices of the several valleys 
in each major sector, as in tables 10 and 11, where the data are given in full and are 
